int ff_intel_h263_decode_picture_header(MpegEncContext *s) { int format; /* picture header */ if (get_bits_long(&s->gb, 22) != 0x20) { av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n"); return -1; } s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */ if (get_bits1(&s->gb) != 1) { av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n"); return -1; /* marker */ } if (get_bits1(&s->gb) != 0) { av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n"); return -1; /* h263 id */ } skip_bits1(&s->gb); /* split screen off */ skip_bits1(&s->gb); /* camera off */ skip_bits1(&s->gb); /* freeze picture release off */ format = get_bits(&s->gb, 3); if (format == 0 || format == 6) { av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n"); return -1; } s->h263_plus = 0; s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb); s->unrestricted_mv = get_bits1(&s->gb); s->h263_long_vectors = s->unrestricted_mv; if (get_bits1(&s->gb) != 0) { av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n"); return -1; /* SAC: off */ } s->obmc= get_bits1(&s->gb); s->pb_frame = get_bits1(&s->gb); if (format < 6) { s->width = ff_h263_format[format][0]; s->height = ff_h263_format[format][1]; s->avctx->sample_aspect_ratio.num = 12; s->avctx->sample_aspect_ratio.den = 11; } else { format = get_bits(&s->gb, 3); if(format == 0 || format == 7){ av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n"); return -1; } if(get_bits(&s->gb, 2)) av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n"); s->loop_filter = get_bits1(&s->gb); if(get_bits1(&s->gb)) av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n"); if(get_bits1(&s->gb)) s->pb_frame = 2; if(get_bits(&s->gb, 5)) av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n"); if(get_bits(&s->gb, 5) != 1) av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n"); } if(format == 6){ int ar = get_bits(&s->gb, 4); skip_bits(&s->gb, 9); // display width skip_bits1(&s->gb); skip_bits(&s->gb, 9); // display height if(ar == 15){ s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height } else { s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar]; } if (s->avctx->sample_aspect_ratio.num == 0) av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n"); } s->chroma_qscale= s->qscale = get_bits(&s->gb, 5); skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */ if(s->pb_frame){ skip_bits(&s->gb, 3); //temporal reference for B-frame skip_bits(&s->gb, 2); //dbquant } /* PEI */ while (get_bits1(&s->gb) != 0) { skip_bits(&s->gb, 8); } s->f_code = 1; s->y_dc_scale_table= s->c_dc_scale_table= ff_mpeg1_dc_scale_table; ff_h263_show_pict_info(s); return 0; }