static int dxa_read_header(AVFormatContext *s, AVFormatParameters *ap) { AVIOContext *pb = s->pb; DXAContext *c = s->priv_data; AVStream *st, *ast; uint32_t tag; int32_t fps; int w, h; int num, den; int flags; tag = avio_rl32(pb); if (tag != MKTAG('D', 'E', 'X', 'A')) return -1; flags = avio_r8(pb); c->frames = avio_rb16(pb); if(!c->frames){ av_log(s, AV_LOG_ERROR, "File contains no frames ???\n"); return -1; } fps = avio_rb32(pb); if(fps > 0){ den = 1000; num = fps; }else if (fps < 0){ den = 100000; num = -fps; }else{ den = 10; num = 1; } w = avio_rb16(pb); h = avio_rb16(pb); c->has_sound = 0; st = av_new_stream(s, 0); if (!st) return -1; // Parse WAV data header if(avio_rl32(pb) == MKTAG('W', 'A', 'V', 'E')){ uint32_t size, fsize; c->has_sound = 1; size = avio_rb32(pb); c->vidpos = avio_tell(pb) + size; avio_skip(pb, 16); fsize = avio_rl32(pb); ast = av_new_stream(s, 0); if (!ast) return -1; ff_get_wav_header(pb, ast->codec, fsize); // find 'data' chunk while(avio_tell(pb) < c->vidpos && !pb->eof_reached){ tag = avio_rl32(pb); fsize = avio_rl32(pb); if(tag == MKTAG('d', 'a', 't', 'a')) break; avio_skip(pb, fsize); } c->bpc = (fsize + c->frames - 1) / c->frames; if(ast->codec->block_align) c->bpc = ((c->bpc + ast->codec->block_align - 1) / ast->codec->block_align) * ast->codec->block_align; c->bytes_left = fsize; c->wavpos = avio_tell(pb); avio_seek(pb, c->vidpos, SEEK_SET); } /* now we are ready: build format streams */ st->codec->codec_type = AVMEDIA_TYPE_VIDEO; st->codec->codec_id = CODEC_ID_DXA; st->codec->width = w; st->codec->height = h; av_reduce(&den, &num, den, num, (1UL<<31)-1); av_set_pts_info(st, 33, num, den); /* flags & 0x80 means that image is interlaced, * flags & 0x40 means that image has double height * either way set true height */ if(flags & 0xC0){ st->codec->height >>= 1; } c->readvid = !c->has_sound; c->vidpos = avio_tell(pb); s->start_time = 0; s->duration = (int64_t)c->frames * AV_TIME_BASE * num / den; av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames); return 0; }