FFmpeg: libavformat/ipmovie.c Source File

00001 /*
00002  * Interplay MVE File Demuxer
00003  * Copyright (c) 2003 The ffmpeg Project
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 
00035 #include "libavutil/intreadwrite.h"
00036 #include "avformat.h"
00037 
00038 /* debugging support: #define DEBUG_IPMOVIE as non-zero to see extremely
00039  * verbose information about the demux process */
00040 #define DEBUG_IPMOVIE 0
00041 
00042 #if DEBUG_IPMOVIE
00043 #undef printf
00044 #define debug_ipmovie printf
00045 #else
00046 static inline void debug_ipmovie(const char *format, ...) { }
00047 #endif
00048 
00049 #define CHUNK_PREAMBLE_SIZE 4
00050 #define OPCODE_PREAMBLE_SIZE 4
00051 
00052 #define CHUNK_INIT_AUDIO   0x0000
00053 #define CHUNK_AUDIO_ONLY   0x0001
00054 #define CHUNK_INIT_VIDEO   0x0002
00055 #define CHUNK_VIDEO        0x0003
00056 #define CHUNK_SHUTDOWN     0x0004
00057 #define CHUNK_END          0x0005
00058 /* these last types are used internally */
00059 #define CHUNK_DONE         0xFFFC
00060 #define CHUNK_NOMEM        0xFFFD
00061 #define CHUNK_EOF          0xFFFE
00062 #define CHUNK_BAD          0xFFFF
00063 
00064 #define OPCODE_END_OF_STREAM           0x00
00065 #define OPCODE_END_OF_CHUNK            0x01
00066 #define OPCODE_CREATE_TIMER            0x02
00067 #define OPCODE_INIT_AUDIO_BUFFERS      0x03
00068 #define OPCODE_START_STOP_AUDIO        0x04
00069 #define OPCODE_INIT_VIDEO_BUFFERS      0x05
00070 #define OPCODE_UNKNOWN_06              0x06
00071 #define OPCODE_SEND_BUFFER             0x07
00072 #define OPCODE_AUDIO_FRAME             0x08
00073 #define OPCODE_SILENCE_FRAME           0x09
00074 #define OPCODE_INIT_VIDEO_MODE         0x0A
00075 #define OPCODE_CREATE_GRADIENT         0x0B
00076 #define OPCODE_SET_PALETTE             0x0C
00077 #define OPCODE_SET_PALETTE_COMPRESSED  0x0D
00078 #define OPCODE_UNKNOWN_0E              0x0E
00079 #define OPCODE_SET_DECODING_MAP        0x0F
00080 #define OPCODE_UNKNOWN_10              0x10
00081 #define OPCODE_VIDEO_DATA              0x11
00082 #define OPCODE_UNKNOWN_12              0x12
00083 #define OPCODE_UNKNOWN_13              0x13
00084 #define OPCODE_UNKNOWN_14              0x14
00085 #define OPCODE_UNKNOWN_15              0x15
00086 
00087 #define PALETTE_COUNT 256
00088 
00089 typedef struct IPMVEContext {
00090 
00091     unsigned char *buf;
00092     int buf_size;
00093 
00094     uint64_t frame_pts_inc;
00095 
00096     unsigned int video_bpp;
00097     unsigned int video_width;
00098     unsigned int video_height;
00099     int64_t video_pts;
00100 
00101     unsigned int audio_bits;
00102     unsigned int audio_channels;
00103     unsigned int audio_sample_rate;
00104     enum CodecID audio_type;
00105     unsigned int audio_frame_count;
00106 
00107     int video_stream_index;
00108     int audio_stream_index;
00109 
00110     int64_t audio_chunk_offset;
00111     int audio_chunk_size;
00112     int64_t video_chunk_offset;
00113     int video_chunk_size;
00114     int64_t decode_map_chunk_offset;
00115     int decode_map_chunk_size;
00116 
00117     int64_t next_chunk_offset;
00118 
00119     AVPaletteControl palette_control;
00120 
00121 } IPMVEContext;
00122 
00123 static int load_ipmovie_packet(IPMVEContext *s, ByteIOContext *pb,
00124     AVPacket *pkt) {
00125 
00126     int chunk_type;
00127 
00128     if (s->audio_chunk_offset) {
00129 
00130         /* adjust for PCM audio by skipping chunk header */
00131         if (s->audio_type != CODEC_ID_INTERPLAY_DPCM) {
00132             s->audio_chunk_offset += 6;
00133             s->audio_chunk_size -= 6;
00134         }
00135 
00136         url_fseek(pb, s->audio_chunk_offset, SEEK_SET);
00137         s->audio_chunk_offset = 0;
00138 
00139         if (s->audio_chunk_size != av_get_packet(pb, pkt, s->audio_chunk_size))
00140             return CHUNK_EOF;
00141 
00142         pkt->stream_index = s->audio_stream_index;
00143         pkt->pts = s->audio_frame_count;
00144 
00145         /* audio frame maintenance */
00146         if (s->audio_type != CODEC_ID_INTERPLAY_DPCM)
00147             s->audio_frame_count +=
00148             (s->audio_chunk_size / s->audio_channels / (s->audio_bits / 8));
00149         else
00150             s->audio_frame_count +=
00151                 (s->audio_chunk_size - 6) / s->audio_channels;
00152 
00153         debug_ipmovie("sending audio frame with pts %"PRId64" (%d audio frames)\n",
00154             pkt->pts, s->audio_frame_count);
00155 
00156         chunk_type = CHUNK_VIDEO;
00157 
00158     } else if (s->decode_map_chunk_offset) {
00159 
00160         /* send both the decode map and the video data together */
00161 
00162         if (av_new_packet(pkt, s->decode_map_chunk_size + s->video_chunk_size))
00163             return CHUNK_NOMEM;
00164 
00165         pkt->pos= s->decode_map_chunk_offset;
00166         url_fseek(pb, s->decode_map_chunk_offset, SEEK_SET);
00167         s->decode_map_chunk_offset = 0;
00168 
00169         if (get_buffer(pb, pkt->data, s->decode_map_chunk_size) !=
00170             s->decode_map_chunk_size) {
00171             av_free_packet(pkt);
00172             return CHUNK_EOF;
00173         }
00174 
00175         url_fseek(pb, s->video_chunk_offset, SEEK_SET);
00176         s->video_chunk_offset = 0;
00177 
00178         if (get_buffer(pb, pkt->data + s->decode_map_chunk_size,
00179             s->video_chunk_size) != s->video_chunk_size) {
00180             av_free_packet(pkt);
00181             return CHUNK_EOF;
00182         }
00183 
00184         pkt->stream_index = s->video_stream_index;
00185         pkt->pts = s->video_pts;
00186 
00187         debug_ipmovie("sending video frame with pts %"PRId64"\n",
00188             pkt->pts);
00189 
00190         s->video_pts += s->frame_pts_inc;
00191 
00192         chunk_type = CHUNK_VIDEO;
00193 
00194     } else {
00195 
00196         url_fseek(pb, s->next_chunk_offset, SEEK_SET);
00197         chunk_type = CHUNK_DONE;
00198 
00199     }
00200 
00201     return chunk_type;
00202 }
00203 
00204 /* This function loads and processes a single chunk in an IP movie file.
00205  * It returns the type of chunk that was processed. */
00206 static int process_ipmovie_chunk(IPMVEContext *s, ByteIOContext *pb,
00207     AVPacket *pkt)
00208 {
00209     unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
00210     int chunk_type;
00211     int chunk_size;
00212     unsigned char opcode_preamble[OPCODE_PREAMBLE_SIZE];
00213     unsigned char opcode_type;
00214     unsigned char opcode_version;
00215     int opcode_size;
00216     unsigned char scratch[1024];
00217     int i, j;
00218     int first_color, last_color;
00219     int audio_flags;
00220     unsigned char r, g, b;
00221 
00222     /* see if there are any pending packets */
00223     chunk_type = load_ipmovie_packet(s, pb, pkt);
00224     if (chunk_type != CHUNK_DONE)
00225         return chunk_type;
00226 
00227     /* read the next chunk, wherever the file happens to be pointing */
00228     if (url_feof(pb))
00229         return CHUNK_EOF;
00230     if (get_buffer(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
00231         CHUNK_PREAMBLE_SIZE)
00232         return CHUNK_BAD;
00233     chunk_size = AV_RL16(&chunk_preamble[0]);
00234     chunk_type = AV_RL16(&chunk_preamble[2]);
00235 
00236     debug_ipmovie("chunk type 0x%04X, 0x%04X bytes: ", chunk_type, chunk_size);
00237 
00238     switch (chunk_type) {
00239 
00240     case CHUNK_INIT_AUDIO:
00241         debug_ipmovie("initialize audio\n");
00242         break;
00243 
00244     case CHUNK_AUDIO_ONLY:
00245         debug_ipmovie("audio only\n");
00246         break;
00247 
00248     case CHUNK_INIT_VIDEO:
00249         debug_ipmovie("initialize video\n");
00250         break;
00251 
00252     case CHUNK_VIDEO:
00253         debug_ipmovie("video (and audio)\n");
00254         break;
00255 
00256     case CHUNK_SHUTDOWN:
00257         debug_ipmovie("shutdown\n");
00258         break;
00259 
00260     case CHUNK_END:
00261         debug_ipmovie("end\n");
00262         break;
00263 
00264     default:
00265         debug_ipmovie("invalid chunk\n");
00266         chunk_type = CHUNK_BAD;
00267         break;
00268 
00269     }
00270 
00271     while ((chunk_size > 0) && (chunk_type != CHUNK_BAD)) {
00272 
00273         /* read the next chunk, wherever the file happens to be pointing */
00274        if (url_feof(pb)) {
00275             chunk_type = CHUNK_EOF;
00276             break;
00277         }
00278         if (get_buffer(pb, opcode_preamble, CHUNK_PREAMBLE_SIZE) !=
00279             CHUNK_PREAMBLE_SIZE) {
00280             chunk_type = CHUNK_BAD;
00281             break;
00282         }
00283 
00284         opcode_size = AV_RL16(&opcode_preamble[0]);
00285         opcode_type = opcode_preamble[2];
00286         opcode_version = opcode_preamble[3];
00287 
00288         chunk_size -= OPCODE_PREAMBLE_SIZE;
00289         chunk_size -= opcode_size;
00290         if (chunk_size < 0) {
00291             debug_ipmovie("chunk_size countdown just went negative\n");
00292             chunk_type = CHUNK_BAD;
00293             break;
00294         }
00295 
00296         debug_ipmovie("  opcode type %02X, version %d, 0x%04X bytes: ",
00297             opcode_type, opcode_version, opcode_size);
00298         switch (opcode_type) {
00299 
00300         case OPCODE_END_OF_STREAM:
00301             debug_ipmovie("end of stream\n");
00302             url_fseek(pb, opcode_size, SEEK_CUR);
00303             break;
00304 
00305         case OPCODE_END_OF_CHUNK:
00306             debug_ipmovie("end of chunk\n");
00307             url_fseek(pb, opcode_size, SEEK_CUR);
00308             break;
00309 
00310         case OPCODE_CREATE_TIMER:
00311             debug_ipmovie("create timer\n");
00312             if ((opcode_version > 0) || (opcode_size > 6)) {
00313                 debug_ipmovie("bad create_timer opcode\n");
00314                 chunk_type = CHUNK_BAD;
00315                 break;
00316             }
00317             if (get_buffer(pb, scratch, opcode_size) !=
00318                 opcode_size) {
00319                 chunk_type = CHUNK_BAD;
00320                 break;
00321             }
00322             s->frame_pts_inc = ((uint64_t)AV_RL32(&scratch[0])) * AV_RL16(&scratch[4]);
00323             debug_ipmovie("  %.2f frames/second (timer div = %d, subdiv = %d)\n",
00324                 1000000.0/s->frame_pts_inc, AV_RL32(&scratch[0]), AV_RL16(&scratch[4]));
00325             break;
00326 
00327         case OPCODE_INIT_AUDIO_BUFFERS:
00328             debug_ipmovie("initialize audio buffers\n");
00329             if ((opcode_version > 1) || (opcode_size > 10)) {
00330                 debug_ipmovie("bad init_audio_buffers opcode\n");
00331                 chunk_type = CHUNK_BAD;
00332                 break;
00333             }
00334             if (get_buffer(pb, scratch, opcode_size) !=
00335                 opcode_size) {
00336                 chunk_type = CHUNK_BAD;
00337                 break;
00338             }
00339             s->audio_sample_rate = AV_RL16(&scratch[4]);
00340             audio_flags = AV_RL16(&scratch[2]);
00341             /* bit 0 of the flags: 0 = mono, 1 = stereo */
00342             s->audio_channels = (audio_flags & 1) + 1;
00343             /* bit 1 of the flags: 0 = 8 bit, 1 = 16 bit */
00344             s->audio_bits = (((audio_flags >> 1) & 1) + 1) * 8;
00345             /* bit 2 indicates compressed audio in version 1 opcode */
00346             if ((opcode_version == 1) && (audio_flags & 0x4))
00347                 s->audio_type = CODEC_ID_INTERPLAY_DPCM;
00348             else if (s->audio_bits == 16)
00349                 s->audio_type = CODEC_ID_PCM_S16LE;
00350             else
00351                 s->audio_type = CODEC_ID_PCM_U8;
00352             debug_ipmovie("audio: %d bits, %d Hz, %s, %s format\n",
00353                 s->audio_bits,
00354                 s->audio_sample_rate,
00355                 (s->audio_channels == 2) ? "stereo" : "mono",
00356                 (s->audio_type == CODEC_ID_INTERPLAY_DPCM) ?
00357                 "Interplay audio" : "PCM");
00358             break;
00359 
00360         case OPCODE_START_STOP_AUDIO:
00361             debug_ipmovie("start/stop audio\n");
00362             url_fseek(pb, opcode_size, SEEK_CUR);
00363             break;
00364 
00365         case OPCODE_INIT_VIDEO_BUFFERS:
00366             debug_ipmovie("initialize video buffers\n");
00367             if ((opcode_version > 2) || (opcode_size > 8)) {
00368                 debug_ipmovie("bad init_video_buffers opcode\n");
00369                 chunk_type = CHUNK_BAD;
00370                 break;
00371             }
00372             if (get_buffer(pb, scratch, opcode_size) !=
00373                 opcode_size) {
00374                 chunk_type = CHUNK_BAD;
00375                 break;
00376             }
00377             s->video_width = AV_RL16(&scratch[0]) * 8;
00378             s->video_height = AV_RL16(&scratch[2]) * 8;
00379             if (opcode_version < 2 || !AV_RL16(&scratch[6])) {
00380                 s->video_bpp = 8;
00381             } else {
00382                 s->video_bpp = 16;
00383             }
00384             debug_ipmovie("video resolution: %d x %d\n",
00385                 s->video_width, s->video_height);
00386             break;
00387 
00388         case OPCODE_UNKNOWN_06:
00389         case OPCODE_UNKNOWN_0E:
00390         case OPCODE_UNKNOWN_10:
00391         case OPCODE_UNKNOWN_12:
00392         case OPCODE_UNKNOWN_13:
00393         case OPCODE_UNKNOWN_14:
00394         case OPCODE_UNKNOWN_15:
00395             debug_ipmovie("unknown (but documented) opcode %02X\n", opcode_type);
00396             url_fseek(pb, opcode_size, SEEK_CUR);
00397             break;
00398 
00399         case OPCODE_SEND_BUFFER:
00400             debug_ipmovie("send buffer\n");
00401             url_fseek(pb, opcode_size, SEEK_CUR);
00402             break;
00403 
00404         case OPCODE_AUDIO_FRAME:
00405             debug_ipmovie("audio frame\n");
00406 
00407             /* log position and move on for now */
00408             s->audio_chunk_offset = url_ftell(pb);
00409             s->audio_chunk_size = opcode_size;
00410             url_fseek(pb, opcode_size, SEEK_CUR);
00411             break;
00412 
00413         case OPCODE_SILENCE_FRAME:
00414             debug_ipmovie("silence frame\n");
00415             url_fseek(pb, opcode_size, SEEK_CUR);
00416             break;
00417 
00418         case OPCODE_INIT_VIDEO_MODE:
00419             debug_ipmovie("initialize video mode\n");
00420             url_fseek(pb, opcode_size, SEEK_CUR);
00421             break;
00422 
00423         case OPCODE_CREATE_GRADIENT:
00424             debug_ipmovie("create gradient\n");
00425             url_fseek(pb, opcode_size, SEEK_CUR);
00426             break;
00427 
00428         case OPCODE_SET_PALETTE:
00429             debug_ipmovie("set palette\n");
00430             /* check for the logical maximum palette size
00431              * (3 * 256 + 4 bytes) */
00432             if (opcode_size > 0x304) {
00433                 debug_ipmovie("demux_ipmovie: set_palette opcode too large\n");
00434                 chunk_type = CHUNK_BAD;
00435                 break;
00436             }
00437             if (get_buffer(pb, scratch, opcode_size) != opcode_size) {
00438                 chunk_type = CHUNK_BAD;
00439                 break;
00440             }
00441 
00442             /* load the palette into internal data structure */
00443             first_color = AV_RL16(&scratch[0]);
00444             last_color = first_color + AV_RL16(&scratch[2]) - 1;
00445             /* sanity check (since they are 16 bit values) */
00446             if ((first_color > 0xFF) || (last_color > 0xFF)) {
00447                 debug_ipmovie("demux_ipmovie: set_palette indexes out of range (%d -> %d)\n",
00448                     first_color, last_color);
00449                 chunk_type = CHUNK_BAD;
00450                 break;
00451             }
00452             j = 4;  /* offset of first palette data */
00453             for (i = first_color; i <= last_color; i++) {
00454                 /* the palette is stored as a 6-bit VGA palette, thus each
00455                  * component is shifted up to a 8-bit range */
00456                 r = scratch[j++] * 4;
00457                 g = scratch[j++] * 4;
00458                 b = scratch[j++] * 4;
00459                 s->palette_control.palette[i] = (r << 16) | (g << 8) | (b);
00460             }
00461             /* indicate a palette change */
00462             s->palette_control.palette_changed = 1;
00463             break;
00464 
00465         case OPCODE_SET_PALETTE_COMPRESSED:
00466             debug_ipmovie("set palette compressed\n");
00467             url_fseek(pb, opcode_size, SEEK_CUR);
00468             break;
00469 
00470         case OPCODE_SET_DECODING_MAP:
00471             debug_ipmovie("set decoding map\n");
00472 
00473             /* log position and move on for now */
00474             s->decode_map_chunk_offset = url_ftell(pb);
00475             s->decode_map_chunk_size = opcode_size;
00476             url_fseek(pb, opcode_size, SEEK_CUR);
00477             break;
00478 
00479         case OPCODE_VIDEO_DATA:
00480             debug_ipmovie("set video data\n");
00481 
00482             /* log position and move on for now */
00483             s->video_chunk_offset = url_ftell(pb);
00484             s->video_chunk_size = opcode_size;
00485             url_fseek(pb, opcode_size, SEEK_CUR);
00486             break;
00487 
00488         default:
00489             debug_ipmovie("*** unknown opcode type\n");
00490             chunk_type = CHUNK_BAD;
00491             break;
00492 
00493         }
00494     }
00495 
00496     /* make a note of where the stream is sitting */
00497     s->next_chunk_offset = url_ftell(pb);
00498 
00499     /* dispatch the first of any pending packets */
00500     if ((chunk_type == CHUNK_VIDEO) || (chunk_type == CHUNK_AUDIO_ONLY))
00501         chunk_type = load_ipmovie_packet(s, pb, pkt);
00502 
00503     return chunk_type;
00504 }
00505 
00506 static const char signature[] = "Interplay MVE File\x1A\0\x1A";
00507 
00508 static int ipmovie_probe(AVProbeData *p)
00509 {
00510     uint8_t *b = p->buf;
00511     uint8_t *b_end = p->buf + p->buf_size - sizeof(signature);
00512     do {
00513         if (memcmp(b++, signature, sizeof(signature)) == 0)
00514             return AVPROBE_SCORE_MAX;
00515     } while (b < b_end);
00516 
00517     return 0;
00518 }
00519 
00520 static int ipmovie_read_header(AVFormatContext *s,
00521                                AVFormatParameters *ap)
00522 {
00523     IPMVEContext *ipmovie = s->priv_data;
00524     ByteIOContext *pb = s->pb;
00525     AVPacket pkt;
00526     AVStream *st;
00527     unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
00528     int chunk_type;
00529     uint8_t signature_buffer[sizeof(signature)];
00530 
00531     get_buffer(pb, signature_buffer, sizeof(signature_buffer));
00532     while (memcmp(signature_buffer, signature, sizeof(signature))) {
00533         memmove(signature_buffer, signature_buffer + 1, sizeof(signature_buffer) - 1);
00534         signature_buffer[sizeof(signature_buffer) - 1] = get_byte(pb);
00535         if (url_feof(pb))
00536             return AVERROR_EOF;
00537     }
00538     /* initialize private context members */
00539     ipmovie->video_pts = ipmovie->audio_frame_count = 0;
00540     ipmovie->audio_chunk_offset = ipmovie->video_chunk_offset =
00541     ipmovie->decode_map_chunk_offset = 0;
00542 
00543     /* on the first read, this will position the stream at the first chunk */
00544     ipmovie->next_chunk_offset = url_ftell(pb) + 4;
00545 
00546     /* process the first chunk which should be CHUNK_INIT_VIDEO */
00547     if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_VIDEO)
00548         return AVERROR_INVALIDDATA;
00549 
00550     /* peek ahead to the next chunk-- if it is an init audio chunk, process
00551      * it; if it is the first video chunk, this is a silent file */
00552     if (get_buffer(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
00553         CHUNK_PREAMBLE_SIZE)
00554         return AVERROR(EIO);
00555     chunk_type = AV_RL16(&chunk_preamble[2]);
00556     url_fseek(pb, -CHUNK_PREAMBLE_SIZE, SEEK_CUR);
00557 
00558     if (chunk_type == CHUNK_VIDEO)
00559         ipmovie->audio_type = CODEC_ID_NONE;  /* no audio */
00560     else if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_AUDIO)
00561         return AVERROR_INVALIDDATA;
00562 
00563     /* initialize the stream decoders */
00564     st = av_new_stream(s, 0);
00565     if (!st)
00566         return AVERROR(ENOMEM);
00567     av_set_pts_info(st, 63, 1, 1000000);
00568     ipmovie->video_stream_index = st->index;
00569     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00570     st->codec->codec_id = CODEC_ID_INTERPLAY_VIDEO;
00571     st->codec->codec_tag = 0;  /* no fourcc */
00572     st->codec->width = ipmovie->video_width;
00573     st->codec->height = ipmovie->video_height;
00574     st->codec->bits_per_coded_sample = ipmovie->video_bpp;
00575 
00576     /* palette considerations */
00577     st->codec->palctrl = &ipmovie->palette_control;
00578 
00579     if (ipmovie->audio_type) {
00580         st = av_new_stream(s, 0);
00581         if (!st)
00582             return AVERROR(ENOMEM);
00583         av_set_pts_info(st, 32, 1, ipmovie->audio_sample_rate);
00584         ipmovie->audio_stream_index = st->index;
00585         st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00586         st->codec->codec_id = ipmovie->audio_type;
00587         st->codec->codec_tag = 0;  /* no tag */
00588         st->codec->channels = ipmovie->audio_channels;
00589         st->codec->sample_rate = ipmovie->audio_sample_rate;
00590         st->codec->bits_per_coded_sample = ipmovie->audio_bits;
00591         st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
00592             st->codec->bits_per_coded_sample;
00593         if (st->codec->codec_id == CODEC_ID_INTERPLAY_DPCM)
00594             st->codec->bit_rate /= 2;
00595         st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
00596     }
00597 
00598     return 0;
00599 }
00600 
00601 static int ipmovie_read_packet(AVFormatContext *s,
00602                                AVPacket *pkt)
00603 {
00604     IPMVEContext *ipmovie = s->priv_data;
00605     ByteIOContext *pb = s->pb;
00606     int ret;
00607 
00608     ret = process_ipmovie_chunk(ipmovie, pb, pkt);
00609     if (ret == CHUNK_BAD)
00610         ret = AVERROR_INVALIDDATA;
00611     else if (ret == CHUNK_EOF)
00612         ret = AVERROR(EIO);
00613     else if (ret == CHUNK_NOMEM)
00614         ret = AVERROR(ENOMEM);
00615     else if (ret == CHUNK_VIDEO)
00616         ret = 0;
00617     else
00618         ret = -1;
00619 
00620     return ret;
00621 }
00622 
00623 AVInputFormat ipmovie_demuxer = {
00624     "ipmovie",
00625     NULL_IF_CONFIG_SMALL("Interplay MVE format"),
00626     sizeof(IPMVEContext),
00627     ipmovie_probe,
00628     ipmovie_read_header,
00629     ipmovie_read_packet,
00630 };