FFmpeg: libavformat/mxfdec.c Source File

00001 /*
00002  * MXF demuxer.
00003  * Copyright (c) 2006 SmartJog S.A., Baptiste Coudurier <baptiste dot coudurier at smartjog dot com>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 /*
00023  * References
00024  * SMPTE 336M KLV Data Encoding Protocol Using Key-Length-Value
00025  * SMPTE 377M MXF File Format Specifications
00026  * SMPTE 378M Operational Pattern 1a
00027  * SMPTE 379M MXF Generic Container
00028  * SMPTE 381M Mapping MPEG Streams into the MXF Generic Container
00029  * SMPTE 382M Mapping AES3 and Broadcast Wave Audio into the MXF Generic Container
00030  * SMPTE 383M Mapping DV-DIF Data to the MXF Generic Container
00031  *
00032  * Principle
00033  * Search for Track numbers which will identify essence element KLV packets.
00034  * Search for SourcePackage which define tracks which contains Track numbers.
00035  * Material Package contains tracks with reference to SourcePackage tracks.
00036  * Search for Descriptors (Picture, Sound) which contains codec info and parameters.
00037  * Assign Descriptors to correct Tracks.
00038  *
00039  * Metadata reading functions read Local Tags, get InstanceUID(0x3C0A) then add MetaDataSet to MXFContext.
00040  * Metadata parsing resolves Strong References to objects.
00041  *
00042  * Simple demuxer, only OP1A supported and some files might not work at all.
00043  * Only tracks with associated descriptors will be decoded. "Highly Desirable" SMPTE 377M D.1
00044  */
00045 
00046 //#define DEBUG
00047 
00048 #include "libavutil/aes.h"
00049 #include "libavcodec/bytestream.h"
00050 #include "avformat.h"
00051 #include "mxf.h"
00052 
00053 typedef struct {
00054     UID uid;
00055     enum MXFMetadataSetType type;
00056     UID source_container_ul;
00057 } MXFCryptoContext;
00058 
00059 typedef struct {
00060     UID uid;
00061     enum MXFMetadataSetType type;
00062     UID source_package_uid;
00063     UID data_definition_ul;
00064     int64_t duration;
00065     int64_t start_position;
00066     int source_track_id;
00067 } MXFStructuralComponent;
00068 
00069 typedef struct {
00070     UID uid;
00071     enum MXFMetadataSetType type;
00072     UID data_definition_ul;
00073     UID *structural_components_refs;
00074     int structural_components_count;
00075     int64_t duration;
00076 } MXFSequence;
00077 
00078 typedef struct {
00079     UID uid;
00080     enum MXFMetadataSetType type;
00081     MXFSequence *sequence; /* mandatory, and only one */
00082     UID sequence_ref;
00083     int track_id;
00084     uint8_t track_number[4];
00085     AVRational edit_rate;
00086 } MXFTrack;
00087 
00088 typedef struct {
00089     UID uid;
00090     enum MXFMetadataSetType type;
00091     UID essence_container_ul;
00092     UID essence_codec_ul;
00093     AVRational sample_rate;
00094     AVRational aspect_ratio;
00095     int width;
00096     int height;
00097     int channels;
00098     int bits_per_sample;
00099     UID *sub_descriptors_refs;
00100     int sub_descriptors_count;
00101     int linked_track_id;
00102     uint8_t *extradata;
00103     int extradata_size;
00104 } MXFDescriptor;
00105 
00106 typedef struct {
00107     UID uid;
00108     enum MXFMetadataSetType type;
00109 } MXFIndexTableSegment;
00110 
00111 typedef struct {
00112     UID uid;
00113     enum MXFMetadataSetType type;
00114     UID package_uid;
00115     UID *tracks_refs;
00116     int tracks_count;
00117     MXFDescriptor *descriptor; /* only one */
00118     UID descriptor_ref;
00119 } MXFPackage;
00120 
00121 typedef struct {
00122     UID uid;
00123     enum MXFMetadataSetType type;
00124 } MXFMetadataSet;
00125 
00126 typedef struct {
00127     UID *packages_refs;
00128     int packages_count;
00129     MXFMetadataSet **metadata_sets;
00130     int metadata_sets_count;
00131     AVFormatContext *fc;
00132     struct AVAES *aesc;
00133     uint8_t *local_tags;
00134     int local_tags_count;
00135 } MXFContext;
00136 
00137 enum MXFWrappingScheme {
00138     Frame,
00139     Clip,
00140 };
00141 
00142 typedef struct {
00143     const UID key;
00144     int (*read)();
00145     int ctx_size;
00146     enum MXFMetadataSetType type;
00147 } MXFMetadataReadTableEntry;
00148 
00149 /* partial keys to match */
00150 static const uint8_t mxf_header_partition_pack_key[]       = { 0x06,0x0e,0x2b,0x34,0x02,0x05,0x01,0x01,0x0d,0x01,0x02,0x01,0x01,0x02 };
00151 static const uint8_t mxf_essence_element_key[]             = { 0x06,0x0e,0x2b,0x34,0x01,0x02,0x01,0x01,0x0d,0x01,0x03,0x01 };
00152 static const uint8_t mxf_klv_key[]                         = { 0x06,0x0e,0x2b,0x34 };
00153 /* complete keys to match */
00154 static const uint8_t mxf_crypto_source_container_ul[]      = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x09,0x06,0x01,0x01,0x02,0x02,0x00,0x00,0x00 };
00155 static const uint8_t mxf_encrypted_triplet_key[]           = { 0x06,0x0e,0x2b,0x34,0x02,0x04,0x01,0x07,0x0d,0x01,0x03,0x01,0x02,0x7e,0x01,0x00 };
00156 static const uint8_t mxf_encrypted_essence_container[]     = { 0x06,0x0e,0x2b,0x34,0x04,0x01,0x01,0x07,0x0d,0x01,0x03,0x01,0x02,0x0b,0x01,0x00 };
00157 static const uint8_t mxf_sony_mpeg4_extradata[]            = { 0x06,0x0e,0x2b,0x34,0x04,0x01,0x01,0x01,0x0e,0x06,0x06,0x02,0x02,0x01,0x00,0x00 };
00158 
00159 #define IS_KLV_KEY(x, y) (!memcmp(x, y, sizeof(y)))
00160 
00161 static int64_t klv_decode_ber_length(ByteIOContext *pb)
00162 {
00163     uint64_t size = get_byte(pb);
00164     if (size & 0x80) { /* long form */
00165         int bytes_num = size & 0x7f;
00166         /* SMPTE 379M 5.3.4 guarantee that bytes_num must not exceed 8 bytes */
00167         if (bytes_num > 8)
00168             return -1;
00169         size = 0;
00170         while (bytes_num--)
00171             size = size << 8 | get_byte(pb);
00172     }
00173     return size;
00174 }
00175 
00176 static int mxf_read_sync(ByteIOContext *pb, const uint8_t *key, unsigned size)
00177 {
00178     int i, b;
00179     for (i = 0; i < size && !url_feof(pb); i++) {
00180         b = get_byte(pb);
00181         if (b == key[0])
00182             i = 0;
00183         else if (b != key[i])
00184             i = -1;
00185     }
00186     return i == size;
00187 }
00188 
00189 static int klv_read_packet(KLVPacket *klv, ByteIOContext *pb)
00190 {
00191     if (!mxf_read_sync(pb, mxf_klv_key, 4))
00192         return -1;
00193     klv->offset = url_ftell(pb) - 4;
00194     memcpy(klv->key, mxf_klv_key, 4);
00195     get_buffer(pb, klv->key + 4, 12);
00196     klv->length = klv_decode_ber_length(pb);
00197     return klv->length == -1 ? -1 : 0;
00198 }
00199 
00200 static int mxf_get_stream_index(AVFormatContext *s, KLVPacket *klv)
00201 {
00202     int i;
00203 
00204     for (i = 0; i < s->nb_streams; i++) {
00205         MXFTrack *track = s->streams[i]->priv_data;
00206         /* SMPTE 379M 7.3 */
00207         if (!memcmp(klv->key + sizeof(mxf_essence_element_key), track->track_number, sizeof(track->track_number)))
00208             return i;
00209     }
00210     /* return 0 if only one stream, for OP Atom files with 0 as track number */
00211     return s->nb_streams == 1 ? 0 : -1;
00212 }
00213 
00214 /* XXX: use AVBitStreamFilter */
00215 static int mxf_get_d10_aes3_packet(ByteIOContext *pb, AVStream *st, AVPacket *pkt, int64_t length)
00216 {
00217     const uint8_t *buf_ptr, *end_ptr;
00218     uint8_t *data_ptr;
00219     int i;
00220 
00221     if (length > 61444) /* worst case PAL 1920 samples 8 channels */
00222         return -1;
00223     av_new_packet(pkt, length);
00224     get_buffer(pb, pkt->data, length);
00225     data_ptr = pkt->data;
00226     end_ptr = pkt->data + length;
00227     buf_ptr = pkt->data + 4; /* skip SMPTE 331M header */
00228     for (; buf_ptr < end_ptr; ) {
00229         for (i = 0; i < st->codec->channels; i++) {
00230             uint32_t sample = bytestream_get_le32(&buf_ptr);
00231             if (st->codec->bits_per_coded_sample == 24)
00232                 bytestream_put_le24(&data_ptr, (sample >> 4) & 0xffffff);
00233             else
00234                 bytestream_put_le16(&data_ptr, (sample >> 12) & 0xffff);
00235         }
00236         buf_ptr += 32 - st->codec->channels*4; // always 8 channels stored SMPTE 331M
00237     }
00238     pkt->size = data_ptr - pkt->data;
00239     return 0;
00240 }
00241 
00242 static int mxf_decrypt_triplet(AVFormatContext *s, AVPacket *pkt, KLVPacket *klv)
00243 {
00244     static const uint8_t checkv[16] = {0x43, 0x48, 0x55, 0x4b, 0x43, 0x48, 0x55, 0x4b, 0x43, 0x48, 0x55, 0x4b, 0x43, 0x48, 0x55, 0x4b};
00245     MXFContext *mxf = s->priv_data;
00246     ByteIOContext *pb = s->pb;
00247     int64_t end = url_ftell(pb) + klv->length;
00248     uint64_t size;
00249     uint64_t orig_size;
00250     uint64_t plaintext_size;
00251     uint8_t ivec[16];
00252     uint8_t tmpbuf[16];
00253     int index;
00254 
00255     if (!mxf->aesc && s->key && s->keylen == 16) {
00256         mxf->aesc = av_malloc(av_aes_size);
00257         if (!mxf->aesc)
00258             return -1;
00259         av_aes_init(mxf->aesc, s->key, 128, 1);
00260     }
00261     // crypto context
00262     url_fskip(pb, klv_decode_ber_length(pb));
00263     // plaintext offset
00264     klv_decode_ber_length(pb);
00265     plaintext_size = get_be64(pb);
00266     // source klv key
00267     klv_decode_ber_length(pb);
00268     get_buffer(pb, klv->key, 16);
00269     if (!IS_KLV_KEY(klv, mxf_essence_element_key))
00270         return -1;
00271     index = mxf_get_stream_index(s, klv);
00272     if (index < 0)
00273         return -1;
00274     // source size
00275     klv_decode_ber_length(pb);
00276     orig_size = get_be64(pb);
00277     if (orig_size < plaintext_size)
00278         return -1;
00279     // enc. code
00280     size = klv_decode_ber_length(pb);
00281     if (size < 32 || size - 32 < orig_size)
00282         return -1;
00283     get_buffer(pb, ivec, 16);
00284     get_buffer(pb, tmpbuf, 16);
00285     if (mxf->aesc)
00286         av_aes_crypt(mxf->aesc, tmpbuf, tmpbuf, 1, ivec, 1);
00287     if (memcmp(tmpbuf, checkv, 16))
00288         av_log(s, AV_LOG_ERROR, "probably incorrect decryption key\n");
00289     size -= 32;
00290     av_get_packet(pb, pkt, size);
00291     size -= plaintext_size;
00292     if (mxf->aesc)
00293         av_aes_crypt(mxf->aesc, &pkt->data[plaintext_size],
00294                      &pkt->data[plaintext_size], size >> 4, ivec, 1);
00295     pkt->size = orig_size;
00296     pkt->stream_index = index;
00297     url_fskip(pb, end - url_ftell(pb));
00298     return 0;
00299 }
00300 
00301 static int mxf_read_packet(AVFormatContext *s, AVPacket *pkt)
00302 {
00303     KLVPacket klv;
00304 
00305     while (!url_feof(s->pb)) {
00306         if (klv_read_packet(&klv, s->pb) < 0)
00307             return -1;
00308         PRINT_KEY(s, "read packet", klv.key);
00309         dprintf(s, "size %lld offset %#llx\n", klv.length, klv.offset);
00310         if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key)) {
00311             int res = mxf_decrypt_triplet(s, pkt, &klv);
00312             if (res < 0) {
00313                 av_log(s, AV_LOG_ERROR, "invalid encoded triplet\n");
00314                 return -1;
00315             }
00316             return 0;
00317         }
00318         if (IS_KLV_KEY(klv.key, mxf_essence_element_key)) {
00319             int index = mxf_get_stream_index(s, &klv);
00320             if (index < 0) {
00321                 av_log(s, AV_LOG_ERROR, "error getting stream index %d\n", AV_RB32(klv.key+12));
00322                 goto skip;
00323             }
00324             if (s->streams[index]->discard == AVDISCARD_ALL)
00325                 goto skip;
00326             /* check for 8 channels AES3 element */
00327             if (klv.key[12] == 0x06 && klv.key[13] == 0x01 && klv.key[14] == 0x10) {
00328                 if (mxf_get_d10_aes3_packet(s->pb, s->streams[index], pkt, klv.length) < 0) {
00329                     av_log(s, AV_LOG_ERROR, "error reading D-10 aes3 frame\n");
00330                     return -1;
00331                 }
00332             } else
00333                 av_get_packet(s->pb, pkt, klv.length);
00334             pkt->stream_index = index;
00335             pkt->pos = klv.offset;
00336             return 0;
00337         } else
00338         skip:
00339             url_fskip(s->pb, klv.length);
00340     }
00341     return AVERROR_EOF;
00342 }
00343 
00344 static int mxf_read_primer_pack(MXFContext *mxf)
00345 {
00346     ByteIOContext *pb = mxf->fc->pb;
00347     int item_num = get_be32(pb);
00348     int item_len = get_be32(pb);
00349 
00350     if (item_len != 18) {
00351         av_log(mxf->fc, AV_LOG_ERROR, "unsupported primer pack item length\n");
00352         return -1;
00353     }
00354     if (item_num > UINT_MAX / item_len)
00355         return -1;
00356     mxf->local_tags_count = item_num;
00357     mxf->local_tags = av_malloc(item_num*item_len);
00358     if (!mxf->local_tags)
00359         return -1;
00360     get_buffer(pb, mxf->local_tags, item_num*item_len);
00361     return 0;
00362 }
00363 
00364 static int mxf_add_metadata_set(MXFContext *mxf, void *metadata_set)
00365 {
00366     if (mxf->metadata_sets_count+1 >= UINT_MAX / sizeof(*mxf->metadata_sets))
00367         return AVERROR(ENOMEM);
00368     mxf->metadata_sets = av_realloc(mxf->metadata_sets, (mxf->metadata_sets_count + 1) * sizeof(*mxf->metadata_sets));
00369     if (!mxf->metadata_sets)
00370         return -1;
00371     mxf->metadata_sets[mxf->metadata_sets_count] = metadata_set;
00372     mxf->metadata_sets_count++;
00373     return 0;
00374 }
00375 
00376 static int mxf_read_cryptographic_context(MXFCryptoContext *cryptocontext, ByteIOContext *pb, int tag, int size, UID uid)
00377 {
00378     if (size != 16)
00379         return -1;
00380     if (IS_KLV_KEY(uid, mxf_crypto_source_container_ul))
00381         get_buffer(pb, cryptocontext->source_container_ul, 16);
00382     return 0;
00383 }
00384 
00385 static int mxf_read_content_storage(MXFContext *mxf, ByteIOContext *pb, int tag)
00386 {
00387     switch (tag) {
00388     case 0x1901:
00389         mxf->packages_count = get_be32(pb);
00390         if (mxf->packages_count >= UINT_MAX / sizeof(UID))
00391             return -1;
00392         mxf->packages_refs = av_malloc(mxf->packages_count * sizeof(UID));
00393         if (!mxf->packages_refs)
00394             return -1;
00395         url_fskip(pb, 4); /* useless size of objects, always 16 according to specs */
00396         get_buffer(pb, (uint8_t *)mxf->packages_refs, mxf->packages_count * sizeof(UID));
00397         break;
00398     }
00399     return 0;
00400 }
00401 
00402 static int mxf_read_source_clip(MXFStructuralComponent *source_clip, ByteIOContext *pb, int tag)
00403 {
00404     switch(tag) {
00405     case 0x0202:
00406         source_clip->duration = get_be64(pb);
00407         break;
00408     case 0x1201:
00409         source_clip->start_position = get_be64(pb);
00410         break;
00411     case 0x1101:
00412         /* UMID, only get last 16 bytes */
00413         url_fskip(pb, 16);
00414         get_buffer(pb, source_clip->source_package_uid, 16);
00415         break;
00416     case 0x1102:
00417         source_clip->source_track_id = get_be32(pb);
00418         break;
00419     }
00420     return 0;
00421 }
00422 
00423 static int mxf_read_material_package(MXFPackage *package, ByteIOContext *pb, int tag)
00424 {
00425     switch(tag) {
00426     case 0x4403:
00427         package->tracks_count = get_be32(pb);
00428         if (package->tracks_count >= UINT_MAX / sizeof(UID))
00429             return -1;
00430         package->tracks_refs = av_malloc(package->tracks_count * sizeof(UID));
00431         if (!package->tracks_refs)
00432             return -1;
00433         url_fskip(pb, 4); /* useless size of objects, always 16 according to specs */
00434         get_buffer(pb, (uint8_t *)package->tracks_refs, package->tracks_count * sizeof(UID));
00435         break;
00436     }
00437     return 0;
00438 }
00439 
00440 static int mxf_read_track(MXFTrack *track, ByteIOContext *pb, int tag)
00441 {
00442     switch(tag) {
00443     case 0x4801:
00444         track->track_id = get_be32(pb);
00445         break;
00446     case 0x4804:
00447         get_buffer(pb, track->track_number, 4);
00448         break;
00449     case 0x4B01:
00450         track->edit_rate.den = get_be32(pb);
00451         track->edit_rate.num = get_be32(pb);
00452         break;
00453     case 0x4803:
00454         get_buffer(pb, track->sequence_ref, 16);
00455         break;
00456     }
00457     return 0;
00458 }
00459 
00460 static int mxf_read_sequence(MXFSequence *sequence, ByteIOContext *pb, int tag)
00461 {
00462     switch(tag) {
00463     case 0x0202:
00464         sequence->duration = get_be64(pb);
00465         break;
00466     case 0x0201:
00467         get_buffer(pb, sequence->data_definition_ul, 16);
00468         break;
00469     case 0x1001:
00470         sequence->structural_components_count = get_be32(pb);
00471         if (sequence->structural_components_count >= UINT_MAX / sizeof(UID))
00472             return -1;
00473         sequence->structural_components_refs = av_malloc(sequence->structural_components_count * sizeof(UID));
00474         if (!sequence->structural_components_refs)
00475             return -1;
00476         url_fskip(pb, 4); /* useless size of objects, always 16 according to specs */
00477         get_buffer(pb, (uint8_t *)sequence->structural_components_refs, sequence->structural_components_count * sizeof(UID));
00478         break;
00479     }
00480     return 0;
00481 }
00482 
00483 static int mxf_read_source_package(MXFPackage *package, ByteIOContext *pb, int tag)
00484 {
00485     switch(tag) {
00486     case 0x4403:
00487         package->tracks_count = get_be32(pb);
00488         if (package->tracks_count >= UINT_MAX / sizeof(UID))
00489             return -1;
00490         package->tracks_refs = av_malloc(package->tracks_count * sizeof(UID));
00491         if (!package->tracks_refs)
00492             return -1;
00493         url_fskip(pb, 4); /* useless size of objects, always 16 according to specs */
00494         get_buffer(pb, (uint8_t *)package->tracks_refs, package->tracks_count * sizeof(UID));
00495         break;
00496     case 0x4401:
00497         /* UMID, only get last 16 bytes */
00498         url_fskip(pb, 16);
00499         get_buffer(pb, package->package_uid, 16);
00500         break;
00501     case 0x4701:
00502         get_buffer(pb, package->descriptor_ref, 16);
00503         break;
00504     }
00505     return 0;
00506 }
00507 
00508 static int mxf_read_index_table_segment(MXFIndexTableSegment *segment, ByteIOContext *pb, int tag)
00509 {
00510     switch(tag) {
00511     case 0x3F05: dprintf(NULL, "EditUnitByteCount %d\n", get_be32(pb)); break;
00512     case 0x3F06: dprintf(NULL, "IndexSID %d\n", get_be32(pb)); break;
00513     case 0x3F07: dprintf(NULL, "BodySID %d\n", get_be32(pb)); break;
00514     case 0x3F0B: dprintf(NULL, "IndexEditRate %d/%d\n", get_be32(pb), get_be32(pb)); break;
00515     case 0x3F0C: dprintf(NULL, "IndexStartPosition %lld\n", get_be64(pb)); break;
00516     case 0x3F0D: dprintf(NULL, "IndexDuration %lld\n", get_be64(pb)); break;
00517     }
00518     return 0;
00519 }
00520 
00521 static void mxf_read_pixel_layout(ByteIOContext *pb, MXFDescriptor *descriptor)
00522 {
00523     int code;
00524 
00525     do {
00526         code = get_byte(pb);
00527         dprintf(NULL, "pixel layout: code %#x\n", code);
00528         switch (code) {
00529         case 0x52: /* R */
00530             descriptor->bits_per_sample += get_byte(pb);
00531             break;
00532         case 0x47: /* G */
00533             descriptor->bits_per_sample += get_byte(pb);
00534             break;
00535         case 0x42: /* B */
00536             descriptor->bits_per_sample += get_byte(pb);
00537             break;
00538         default:
00539             get_byte(pb);
00540         }
00541     } while (code != 0); /* SMPTE 377M E.2.46 */
00542 }
00543 
00544 static int mxf_read_generic_descriptor(MXFDescriptor *descriptor, ByteIOContext *pb, int tag, int size, UID uid)
00545 {
00546     switch(tag) {
00547     case 0x3F01:
00548         descriptor->sub_descriptors_count = get_be32(pb);
00549         if (descriptor->sub_descriptors_count >= UINT_MAX / sizeof(UID))
00550             return -1;
00551         descriptor->sub_descriptors_refs = av_malloc(descriptor->sub_descriptors_count * sizeof(UID));
00552         if (!descriptor->sub_descriptors_refs)
00553             return -1;
00554         url_fskip(pb, 4); /* useless size of objects, always 16 according to specs */
00555         get_buffer(pb, (uint8_t *)descriptor->sub_descriptors_refs, descriptor->sub_descriptors_count * sizeof(UID));
00556         break;
00557     case 0x3004:
00558         get_buffer(pb, descriptor->essence_container_ul, 16);
00559         break;
00560     case 0x3006:
00561         descriptor->linked_track_id = get_be32(pb);
00562         break;
00563     case 0x3201: /* PictureEssenceCoding */
00564         get_buffer(pb, descriptor->essence_codec_ul, 16);
00565         break;
00566     case 0x3203:
00567         descriptor->width = get_be32(pb);
00568         break;
00569     case 0x3202:
00570         descriptor->height = get_be32(pb);
00571         break;
00572     case 0x320E:
00573         descriptor->aspect_ratio.num = get_be32(pb);
00574         descriptor->aspect_ratio.den = get_be32(pb);
00575         break;
00576     case 0x3D03:
00577         descriptor->sample_rate.num = get_be32(pb);
00578         descriptor->sample_rate.den = get_be32(pb);
00579         break;
00580     case 0x3D06: /* SoundEssenceCompression */
00581         get_buffer(pb, descriptor->essence_codec_ul, 16);
00582         break;
00583     case 0x3D07:
00584         descriptor->channels = get_be32(pb);
00585         break;
00586     case 0x3D01:
00587         descriptor->bits_per_sample = get_be32(pb);
00588         break;
00589     case 0x3401:
00590         mxf_read_pixel_layout(pb, descriptor);
00591         break;
00592     default:
00593         /* Private uid used by SONY C0023S01.mxf */
00594         if (IS_KLV_KEY(uid, mxf_sony_mpeg4_extradata)) {
00595             descriptor->extradata = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00596             if (!descriptor->extradata)
00597                 return -1;
00598             descriptor->extradata_size = size;
00599             get_buffer(pb, descriptor->extradata, size);
00600         }
00601         break;
00602     }
00603     return 0;
00604 }
00605 
00606 /*
00607  * Match an uid independently of the version byte and up to len common bytes
00608  * Returns: boolean
00609  */
00610 static int mxf_match_uid(const UID key, const UID uid, int len)
00611 {
00612     int i;
00613     for (i = 0; i < len; i++) {
00614         if (i != 7 && key[i] != uid[i])
00615             return 0;
00616     }
00617     return 1;
00618 }
00619 
00620 static const MXFCodecUL *mxf_get_codec_ul(const MXFCodecUL *uls, UID *uid)
00621 {
00622     while (uls->uid[0]) {
00623         if(mxf_match_uid(uls->uid, *uid, uls->matching_len))
00624             break;
00625         uls++;
00626     }
00627     return uls;
00628 }
00629 
00630 static void *mxf_resolve_strong_ref(MXFContext *mxf, UID *strong_ref, enum MXFMetadataSetType type)
00631 {
00632     int i;
00633 
00634     if (!strong_ref)
00635         return NULL;
00636     for (i = 0; i < mxf->metadata_sets_count; i++) {
00637         if (!memcmp(*strong_ref, mxf->metadata_sets[i]->uid, 16) &&
00638             (type == AnyType || mxf->metadata_sets[i]->type == type)) {
00639             return mxf->metadata_sets[i];
00640         }
00641     }
00642     return NULL;
00643 }
00644 
00645 static const MXFCodecUL mxf_essence_container_uls[] = {
00646     // video essence container uls
00647     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x02,0x0D,0x01,0x03,0x01,0x02,0x04,0x60,0x01 }, 14, CODEC_ID_MPEG2VIDEO }, /* MPEG-ES Frame wrapped */
00648     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x01,0x0D,0x01,0x03,0x01,0x02,0x02,0x41,0x01 }, 14,    CODEC_ID_DVVIDEO }, /* DV 625 25mbps */
00649     // sound essence container uls
00650     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x01,0x0D,0x01,0x03,0x01,0x02,0x06,0x01,0x00 }, 14, CODEC_ID_PCM_S16LE }, /* BWF Frame wrapped */
00651     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x02,0x0D,0x01,0x03,0x01,0x02,0x04,0x40,0x01 }, 14,       CODEC_ID_MP2 }, /* MPEG-ES Frame wrapped, 0x40 ??? stream id */
00652     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x01,0x0D,0x01,0x03,0x01,0x02,0x01,0x01,0x01 }, 14, CODEC_ID_PCM_S16LE }, /* D-10 Mapping 50Mbps PAL Extended Template */
00653     { { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 },  0,      CODEC_ID_NONE },
00654 };
00655 
00656 static int mxf_parse_structural_metadata(MXFContext *mxf)
00657 {
00658     MXFPackage *material_package = NULL;
00659     MXFPackage *temp_package = NULL;
00660     int i, j, k;
00661 
00662     dprintf(mxf->fc, "metadata sets count %d\n", mxf->metadata_sets_count);
00663     /* TODO: handle multiple material packages (OP3x) */
00664     for (i = 0; i < mxf->packages_count; i++) {
00665         material_package = mxf_resolve_strong_ref(mxf, &mxf->packages_refs[i], MaterialPackage);
00666         if (material_package) break;
00667     }
00668     if (!material_package) {
00669         av_log(mxf->fc, AV_LOG_ERROR, "no material package found\n");
00670         return -1;
00671     }
00672 
00673     for (i = 0; i < material_package->tracks_count; i++) {
00674         MXFPackage *source_package = NULL;
00675         MXFTrack *material_track = NULL;
00676         MXFTrack *source_track = NULL;
00677         MXFTrack *temp_track = NULL;
00678         MXFDescriptor *descriptor = NULL;
00679         MXFStructuralComponent *component = NULL;
00680         UID *essence_container_ul = NULL;
00681         const MXFCodecUL *codec_ul = NULL;
00682         const MXFCodecUL *container_ul = NULL;
00683         AVStream *st;
00684 
00685         if (!(material_track = mxf_resolve_strong_ref(mxf, &material_package->tracks_refs[i], Track))) {
00686             av_log(mxf->fc, AV_LOG_ERROR, "could not resolve material track strong ref\n");
00687             continue;
00688         }
00689 
00690         if (!(material_track->sequence = mxf_resolve_strong_ref(mxf, &material_track->sequence_ref, Sequence))) {
00691             av_log(mxf->fc, AV_LOG_ERROR, "could not resolve material track sequence strong ref\n");
00692             continue;
00693         }
00694 
00695         /* TODO: handle multiple source clips */
00696         for (j = 0; j < material_track->sequence->structural_components_count; j++) {
00697             /* TODO: handle timecode component */
00698             component = mxf_resolve_strong_ref(mxf, &material_track->sequence->structural_components_refs[j], SourceClip);
00699             if (!component)
00700                 continue;
00701 
00702             for (k = 0; k < mxf->packages_count; k++) {
00703                 temp_package = mxf_resolve_strong_ref(mxf, &mxf->packages_refs[k], SourcePackage);
00704                 if (!temp_package)
00705                     continue;
00706                 if (!memcmp(temp_package->package_uid, component->source_package_uid, 16)) {
00707                     source_package = temp_package;
00708                     break;
00709                 }
00710             }
00711             if (!source_package) {
00712                 av_log(mxf->fc, AV_LOG_ERROR, "material track %d: no corresponding source package found\n", material_track->track_id);
00713                 break;
00714             }
00715             for (k = 0; k < source_package->tracks_count; k++) {
00716                 if (!(temp_track = mxf_resolve_strong_ref(mxf, &source_package->tracks_refs[k], Track))) {
00717                     av_log(mxf->fc, AV_LOG_ERROR, "could not resolve source track strong ref\n");
00718                     return -1;
00719                 }
00720                 if (temp_track->track_id == component->source_track_id) {
00721                     source_track = temp_track;
00722                     break;
00723                 }
00724             }
00725             if (!source_track) {
00726                 av_log(mxf->fc, AV_LOG_ERROR, "material track %d: no corresponding source track found\n", material_track->track_id);
00727                 break;
00728             }
00729         }
00730         if (!source_track)
00731             continue;
00732 
00733         st = av_new_stream(mxf->fc, source_track->track_id);
00734         if (!st) {
00735             av_log(mxf->fc, AV_LOG_ERROR, "could not allocate stream\n");
00736             return -1;
00737         }
00738         st->priv_data = source_track;
00739         st->duration = component->duration;
00740         if (st->duration == -1)
00741             st->duration = AV_NOPTS_VALUE;
00742         st->start_time = component->start_position;
00743         av_set_pts_info(st, 64, material_track->edit_rate.num, material_track->edit_rate.den);
00744 
00745         if (!(source_track->sequence = mxf_resolve_strong_ref(mxf, &source_track->sequence_ref, Sequence))) {
00746             av_log(mxf->fc, AV_LOG_ERROR, "could not resolve source track sequence strong ref\n");
00747             return -1;
00748         }
00749 
00750         PRINT_KEY(mxf->fc, "data definition   ul", source_track->sequence->data_definition_ul);
00751         codec_ul = mxf_get_codec_ul(ff_mxf_data_definition_uls, &source_track->sequence->data_definition_ul);
00752         st->codec->codec_type = codec_ul->id;
00753 
00754         source_package->descriptor = mxf_resolve_strong_ref(mxf, &source_package->descriptor_ref, AnyType);
00755         if (source_package->descriptor) {
00756             if (source_package->descriptor->type == MultipleDescriptor) {
00757                 for (j = 0; j < source_package->descriptor->sub_descriptors_count; j++) {
00758                     MXFDescriptor *sub_descriptor = mxf_resolve_strong_ref(mxf, &source_package->descriptor->sub_descriptors_refs[j], Descriptor);
00759 
00760                     if (!sub_descriptor) {
00761                         av_log(mxf->fc, AV_LOG_ERROR, "could not resolve sub descriptor strong ref\n");
00762                         continue;
00763                     }
00764                     if (sub_descriptor->linked_track_id == source_track->track_id) {
00765                         descriptor = sub_descriptor;
00766                         break;
00767                     }
00768                 }
00769             } else if (source_package->descriptor->type == Descriptor)
00770                 descriptor = source_package->descriptor;
00771         }
00772         if (!descriptor) {
00773             av_log(mxf->fc, AV_LOG_INFO, "source track %d: stream %d, no descriptor found\n", source_track->track_id, st->index);
00774             continue;
00775         }
00776         PRINT_KEY(mxf->fc, "essence codec     ul", descriptor->essence_codec_ul);
00777         PRINT_KEY(mxf->fc, "essence container ul", descriptor->essence_container_ul);
00778         essence_container_ul = &descriptor->essence_container_ul;
00779         /* HACK: replacing the original key with mxf_encrypted_essence_container
00780          * is not allowed according to s429-6, try to find correct information anyway */
00781         if (IS_KLV_KEY(essence_container_ul, mxf_encrypted_essence_container)) {
00782             av_log(mxf->fc, AV_LOG_INFO, "broken encrypted mxf file\n");
00783             for (k = 0; k < mxf->metadata_sets_count; k++) {
00784                 MXFMetadataSet *metadata = mxf->metadata_sets[k];
00785                 if (metadata->type == CryptoContext) {
00786                     essence_container_ul = &((MXFCryptoContext *)metadata)->source_container_ul;
00787                     break;
00788                 }
00789             }
00790         }
00791         /* TODO: drop PictureEssenceCoding and SoundEssenceCompression, only check EssenceContainer */
00792         codec_ul = mxf_get_codec_ul(ff_mxf_codec_uls, &descriptor->essence_codec_ul);
00793         st->codec->codec_id = codec_ul->id;
00794         if (descriptor->extradata) {
00795             st->codec->extradata = descriptor->extradata;
00796             st->codec->extradata_size = descriptor->extradata_size;
00797         }
00798         if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
00799             container_ul = mxf_get_codec_ul(mxf_essence_container_uls, essence_container_ul);
00800             if (st->codec->codec_id == CODEC_ID_NONE)
00801                 st->codec->codec_id = container_ul->id;
00802             st->codec->width = descriptor->width;
00803             st->codec->height = descriptor->height;
00804             st->codec->bits_per_coded_sample = descriptor->bits_per_sample; /* Uncompressed */
00805             st->need_parsing = AVSTREAM_PARSE_HEADERS;
00806         } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
00807             container_ul = mxf_get_codec_ul(mxf_essence_container_uls, essence_container_ul);
00808             if (st->codec->codec_id == CODEC_ID_NONE)
00809                 st->codec->codec_id = container_ul->id;
00810             st->codec->channels = descriptor->channels;
00811             st->codec->bits_per_coded_sample = descriptor->bits_per_sample;
00812             st->codec->sample_rate = descriptor->sample_rate.num / descriptor->sample_rate.den;
00813             /* TODO: implement CODEC_ID_RAWAUDIO */
00814             if (st->codec->codec_id == CODEC_ID_PCM_S16LE) {
00815                 if (descriptor->bits_per_sample == 24)
00816                     st->codec->codec_id = CODEC_ID_PCM_S24LE;
00817                 else if (descriptor->bits_per_sample == 32)
00818                     st->codec->codec_id = CODEC_ID_PCM_S32LE;
00819             } else if (st->codec->codec_id == CODEC_ID_PCM_S16BE) {
00820                 if (descriptor->bits_per_sample == 24)
00821                     st->codec->codec_id = CODEC_ID_PCM_S24BE;
00822                 else if (descriptor->bits_per_sample == 32)
00823                     st->codec->codec_id = CODEC_ID_PCM_S32BE;
00824             } else if (st->codec->codec_id == CODEC_ID_MP2) {
00825                 st->need_parsing = AVSTREAM_PARSE_FULL;
00826             }
00827         }
00828         if (st->codec->codec_type != AVMEDIA_TYPE_DATA && (*essence_container_ul)[15] > 0x01) {
00829             av_log(mxf->fc, AV_LOG_WARNING, "only frame wrapped mappings are correctly supported\n");
00830             st->need_parsing = AVSTREAM_PARSE_FULL;
00831         }
00832     }
00833     return 0;
00834 }
00835 
00836 static const MXFMetadataReadTableEntry mxf_metadata_read_table[] = {
00837     { { 0x06,0x0E,0x2B,0x34,0x02,0x05,0x01,0x01,0x0d,0x01,0x02,0x01,0x01,0x05,0x01,0x00 }, mxf_read_primer_pack },
00838     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x18,0x00 }, mxf_read_content_storage, 0, AnyType },
00839     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x37,0x00 }, mxf_read_source_package, sizeof(MXFPackage), SourcePackage },
00840     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x36,0x00 }, mxf_read_material_package, sizeof(MXFPackage), MaterialPackage },
00841     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x0F,0x00 }, mxf_read_sequence, sizeof(MXFSequence), Sequence },
00842     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x11,0x00 }, mxf_read_source_clip, sizeof(MXFStructuralComponent), SourceClip },
00843     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x44,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), MultipleDescriptor },
00844     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x42,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* Generic Sound */
00845     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x28,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* CDCI */
00846     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x29,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* RGBA */
00847     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x51,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* MPEG 2 Video */
00848     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x48,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* Wave */
00849     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x47,0x00 }, mxf_read_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* AES3 */
00850     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x3A,0x00 }, mxf_read_track, sizeof(MXFTrack), Track }, /* Static Track */
00851     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x3B,0x00 }, mxf_read_track, sizeof(MXFTrack), Track }, /* Generic Track */
00852     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x04,0x01,0x02,0x02,0x00,0x00 }, mxf_read_cryptographic_context, sizeof(MXFCryptoContext), CryptoContext },
00853     { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x02,0x01,0x01,0x10,0x01,0x00 }, mxf_read_index_table_segment, sizeof(MXFIndexTableSegment), IndexTableSegment },
00854     { { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }, NULL, 0, AnyType },
00855 };
00856 
00857 static int mxf_read_local_tags(MXFContext *mxf, KLVPacket *klv, int (*read_child)(), int ctx_size, enum MXFMetadataSetType type)
00858 {
00859     ByteIOContext *pb = mxf->fc->pb;
00860     MXFMetadataSet *ctx = ctx_size ? av_mallocz(ctx_size) : mxf;
00861     uint64_t klv_end = url_ftell(pb) + klv->length;
00862 
00863     if (!ctx)
00864         return -1;
00865     while (url_ftell(pb) + 4 < klv_end) {
00866         int tag = get_be16(pb);
00867         int size = get_be16(pb); /* KLV specified by 0x53 */
00868         uint64_t next = url_ftell(pb) + size;
00869         UID uid = {0};
00870 
00871         dprintf(mxf->fc, "local tag %#04x size %d\n", tag, size);
00872         if (!size) { /* ignore empty tag, needed for some files with empty UMID tag */
00873             av_log(mxf->fc, AV_LOG_ERROR, "local tag %#04x with 0 size\n", tag);
00874             continue;
00875         }
00876         if (tag > 0x7FFF) { /* dynamic tag */
00877             int i;
00878             for (i = 0; i < mxf->local_tags_count; i++) {
00879                 int local_tag = AV_RB16(mxf->local_tags+i*18);
00880                 if (local_tag == tag) {
00881                     memcpy(uid, mxf->local_tags+i*18+2, 16);
00882                     dprintf(mxf->fc, "local tag %#04x\n", local_tag);
00883                     PRINT_KEY(mxf->fc, "uid", uid);
00884                 }
00885             }
00886         }
00887         if (ctx_size && tag == 0x3C0A)
00888             get_buffer(pb, ctx->uid, 16);
00889         else if (read_child(ctx, pb, tag, size, uid) < 0)
00890             return -1;
00891 
00892         url_fseek(pb, next, SEEK_SET);
00893     }
00894     if (ctx_size) ctx->type = type;
00895     return ctx_size ? mxf_add_metadata_set(mxf, ctx) : 0;
00896 }
00897 
00898 static int mxf_read_header(AVFormatContext *s, AVFormatParameters *ap)
00899 {
00900     MXFContext *mxf = s->priv_data;
00901     KLVPacket klv;
00902 
00903     if (!mxf_read_sync(s->pb, mxf_header_partition_pack_key, 14)) {
00904         av_log(s, AV_LOG_ERROR, "could not find header partition pack key\n");
00905         return -1;
00906     }
00907     url_fseek(s->pb, -14, SEEK_CUR);
00908     mxf->fc = s;
00909     while (!url_feof(s->pb)) {
00910         const MXFMetadataReadTableEntry *metadata;
00911 
00912         if (klv_read_packet(&klv, s->pb) < 0)
00913             return -1;
00914         PRINT_KEY(s, "read header", klv.key);
00915         dprintf(s, "size %lld offset %#llx\n", klv.length, klv.offset);
00916         if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key) ||
00917             IS_KLV_KEY(klv.key, mxf_essence_element_key)) {
00918             /* FIXME avoid seek */
00919             url_fseek(s->pb, klv.offset, SEEK_SET);
00920             break;
00921         }
00922 
00923         for (metadata = mxf_metadata_read_table; metadata->read; metadata++) {
00924             if (IS_KLV_KEY(klv.key, metadata->key)) {
00925                 int (*read)() = klv.key[5] == 0x53 ? mxf_read_local_tags : metadata->read;
00926                 if (read(mxf, &klv, metadata->read, metadata->ctx_size, metadata->type) < 0) {
00927                     av_log(s, AV_LOG_ERROR, "error reading header metadata\n");
00928                     return -1;
00929                 }
00930                 break;
00931             }
00932         }
00933         if (!metadata->read)
00934             url_fskip(s->pb, klv.length);
00935     }
00936     return mxf_parse_structural_metadata(mxf);
00937 }
00938 
00939 static int mxf_read_close(AVFormatContext *s)
00940 {
00941     MXFContext *mxf = s->priv_data;
00942     int i;
00943 
00944     av_freep(&mxf->packages_refs);
00945 
00946     for (i = 0; i < s->nb_streams; i++)
00947         s->streams[i]->priv_data = NULL;
00948 
00949     for (i = 0; i < mxf->metadata_sets_count; i++) {
00950         switch (mxf->metadata_sets[i]->type) {
00951         case MultipleDescriptor:
00952             av_freep(&((MXFDescriptor *)mxf->metadata_sets[i])->sub_descriptors_refs);
00953             break;
00954         case Sequence:
00955             av_freep(&((MXFSequence *)mxf->metadata_sets[i])->structural_components_refs);
00956             break;
00957         case SourcePackage:
00958         case MaterialPackage:
00959             av_freep(&((MXFPackage *)mxf->metadata_sets[i])->tracks_refs);
00960             break;
00961         default:
00962             break;
00963         }
00964         av_freep(&mxf->metadata_sets[i]);
00965     }
00966     av_freep(&mxf->metadata_sets);
00967     av_freep(&mxf->aesc);
00968     av_freep(&mxf->local_tags);
00969     return 0;
00970 }
00971 
00972 static int mxf_probe(AVProbeData *p) {
00973     uint8_t *bufp = p->buf;
00974     uint8_t *end = p->buf + p->buf_size;
00975 
00976     if (p->buf_size < sizeof(mxf_header_partition_pack_key))
00977         return 0;
00978 
00979     /* Must skip Run-In Sequence and search for MXF header partition pack key SMPTE 377M 5.5 */
00980     end -= sizeof(mxf_header_partition_pack_key);
00981     for (; bufp < end; bufp++) {
00982         if (IS_KLV_KEY(bufp, mxf_header_partition_pack_key))
00983             return AVPROBE_SCORE_MAX;
00984     }
00985     return 0;
00986 }
00987 
00988 /* rudimentary byte seek */
00989 /* XXX: use MXF Index */
00990 static int mxf_read_seek(AVFormatContext *s, int stream_index, int64_t sample_time, int flags)
00991 {
00992     AVStream *st = s->streams[stream_index];
00993     int64_t seconds;
00994 
00995     if (!s->bit_rate)
00996         return -1;
00997     if (sample_time < 0)
00998         sample_time = 0;
00999     seconds = av_rescale(sample_time, st->time_base.num, st->time_base.den);
01000     url_fseek(s->pb, (s->bit_rate * seconds) >> 3, SEEK_SET);
01001     av_update_cur_dts(s, st, sample_time);
01002     return 0;
01003 }
01004 
01005 AVInputFormat mxf_demuxer = {
01006     "mxf",
01007     NULL_IF_CONFIG_SMALL("Material eXchange Format"),
01008     sizeof(MXFContext),
01009     mxf_probe,
01010     mxf_read_header,
01011     mxf_read_packet,
01012     mxf_read_close,
01013     mxf_read_seek,
01014 };