FFmpeg: libavformat/dxa.c Source File

00001 /*
00002  * DXA demuxer
00003  * Copyright (c) 2007 Konstantin Shishkov
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 #include "libavutil/intreadwrite.h"
00023 #include "avformat.h"
00024 #include "riff.h"
00025 
00026 #define DXA_EXTRA_SIZE  9
00027 
00028 typedef struct{
00029     int frames;
00030     int has_sound;
00031     int bpc;
00032     uint32_t bytes_left;
00033     int64_t wavpos, vidpos;
00034     int readvid;
00035 }DXAContext;
00036 
00037 static int dxa_probe(AVProbeData *p)
00038 {
00039     /* check file header */
00040     if (p->buf[0] == 'D' && p->buf[1] == 'E' &&
00041         p->buf[2] == 'X' && p->buf[3] == 'A')
00042         return AVPROBE_SCORE_MAX;
00043     else
00044         return 0;
00045 }
00046 
00047 static int dxa_read_header(AVFormatContext *s, AVFormatParameters *ap)
00048 {
00049     ByteIOContext *pb = s->pb;
00050     DXAContext *c = s->priv_data;
00051     AVStream *st, *ast;
00052     uint32_t tag;
00053     int32_t fps;
00054     int w, h;
00055     int num, den;
00056     int flags;
00057 
00058     tag = get_le32(pb);
00059     if (tag != MKTAG('D', 'E', 'X', 'A'))
00060         return -1;
00061     flags = get_byte(pb);
00062     c->frames = get_be16(pb);
00063     if(!c->frames){
00064         av_log(s, AV_LOG_ERROR, "File contains no frames ???\n");
00065         return -1;
00066     }
00067 
00068     fps = get_be32(pb);
00069     if(fps > 0){
00070         den = 1000;
00071         num = fps;
00072     }else if (fps < 0){
00073         den = 100000;
00074         num = -fps;
00075     }else{
00076         den = 10;
00077         num = 1;
00078     }
00079     w = get_be16(pb);
00080     h = get_be16(pb);
00081     c->has_sound = 0;
00082 
00083     st = av_new_stream(s, 0);
00084     if (!st)
00085         return -1;
00086 
00087     // Parse WAV data header
00088     if(get_le32(pb) == MKTAG('W', 'A', 'V', 'E')){
00089         uint32_t size, fsize;
00090         c->has_sound = 1;
00091         size = get_be32(pb);
00092         c->vidpos = url_ftell(pb) + size;
00093         url_fskip(pb, 16);
00094         fsize = get_le32(pb);
00095 
00096         ast = av_new_stream(s, 0);
00097         if (!ast)
00098             return -1;
00099         get_wav_header(pb, ast->codec, fsize);
00100         // find 'data' chunk
00101         while(url_ftell(pb) < c->vidpos && !url_feof(pb)){
00102             tag = get_le32(pb);
00103             fsize = get_le32(pb);
00104             if(tag == MKTAG('d', 'a', 't', 'a')) break;
00105             url_fskip(pb, fsize);
00106         }
00107         c->bpc = (fsize + c->frames - 1) / c->frames;
00108         if(ast->codec->block_align)
00109             c->bpc = ((c->bpc + ast->codec->block_align - 1) / ast->codec->block_align) * ast->codec->block_align;
00110         c->bytes_left = fsize;
00111         c->wavpos = url_ftell(pb);
00112         url_fseek(pb, c->vidpos, SEEK_SET);
00113     }
00114 
00115     /* now we are ready: build format streams */
00116     st->codec->codec_type = CODEC_TYPE_VIDEO;
00117     st->codec->codec_id   = CODEC_ID_DXA;
00118     st->codec->width      = w;
00119     st->codec->height     = h;
00120     av_reduce(&den, &num, den, num, (1UL<<31)-1);
00121     av_set_pts_info(st, 33, num, den);
00122     /* flags & 0x80 means that image is interlaced,
00123      * flags & 0x40 means that image has double height
00124      * either way set true height
00125      */
00126     if(flags & 0xC0){
00127         st->codec->height >>= 1;
00128     }
00129     c->readvid = !c->has_sound;
00130     c->vidpos  = url_ftell(pb);
00131     s->start_time = 0;
00132     s->duration = (int64_t)c->frames * AV_TIME_BASE * num / den;
00133     av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames);
00134 
00135     return 0;
00136 }
00137 
00138 static int dxa_read_packet(AVFormatContext *s, AVPacket *pkt)
00139 {
00140     DXAContext *c = s->priv_data;
00141     int ret;
00142     uint32_t size;
00143     uint8_t buf[DXA_EXTRA_SIZE], pal[768+4];
00144     int pal_size = 0;
00145 
00146     if(!c->readvid && c->has_sound && c->bytes_left){
00147         c->readvid = 1;
00148         url_fseek(s->pb, c->wavpos, SEEK_SET);
00149         size = FFMIN(c->bytes_left, c->bpc);
00150         ret = av_get_packet(s->pb, pkt, size);
00151         pkt->stream_index = 1;
00152         if(ret != size)
00153             return AVERROR(EIO);
00154         c->bytes_left -= size;
00155         c->wavpos = url_ftell(s->pb);
00156         return 0;
00157     }
00158     url_fseek(s->pb, c->vidpos, SEEK_SET);
00159     while(!url_feof(s->pb) && c->frames){
00160         get_buffer(s->pb, buf, 4);
00161         switch(AV_RL32(buf)){
00162         case MKTAG('N', 'U', 'L', 'L'):
00163             if(av_new_packet(pkt, 4 + pal_size) < 0)
00164                 return AVERROR(ENOMEM);
00165             pkt->stream_index = 0;
00166             if(pal_size) memcpy(pkt->data, pal, pal_size);
00167             memcpy(pkt->data + pal_size, buf, 4);
00168             c->frames--;
00169             c->vidpos = url_ftell(s->pb);
00170             c->readvid = 0;
00171             return 0;
00172         case MKTAG('C', 'M', 'A', 'P'):
00173             pal_size = 768+4;
00174             memcpy(pal, buf, 4);
00175             get_buffer(s->pb, pal + 4, 768);
00176             break;
00177         case MKTAG('F', 'R', 'A', 'M'):
00178             get_buffer(s->pb, buf + 4, DXA_EXTRA_SIZE - 4);
00179             size = AV_RB32(buf + 5);
00180             if(size > 0xFFFFFF){
00181                 av_log(s, AV_LOG_ERROR, "Frame size is too big: %d\n", size);
00182                 return -1;
00183             }
00184             if(av_new_packet(pkt, size + DXA_EXTRA_SIZE + pal_size) < 0)
00185                 return AVERROR(ENOMEM);
00186             memcpy(pkt->data + pal_size, buf, DXA_EXTRA_SIZE);
00187             ret = get_buffer(s->pb, pkt->data + DXA_EXTRA_SIZE + pal_size, size);
00188             if(ret != size){
00189                 av_free_packet(pkt);
00190                 return AVERROR(EIO);
00191             }
00192             if(pal_size) memcpy(pkt->data, pal, pal_size);
00193             pkt->stream_index = 0;
00194             c->frames--;
00195             c->vidpos = url_ftell(s->pb);
00196             c->readvid = 0;
00197             return 0;
00198         default:
00199             av_log(s, AV_LOG_ERROR, "Unknown tag %c%c%c%c\n", buf[0], buf[1], buf[2], buf[3]);
00200             return -1;
00201         }
00202     }
00203     return AVERROR(EIO);
00204 }
00205 
00206 AVInputFormat dxa_demuxer = {
00207     "dxa",
00208     NULL_IF_CONFIG_SMALL("DXA"),
00209     sizeof(DXAContext),
00210     dxa_probe,
00211     dxa_read_header,
00212     dxa_read_packet,
00213 };