int 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 != 7) { av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n"); return -1; } s->h263_plus = 0; s->pict_type = I_TYPE + 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 */ } if (get_bits1(&s->gb) != 0) { s->obmc= 1; av_log(s->avctx, AV_LOG_ERROR, "Advanced Prediction Mode not supported\n"); // return -1; /* advanced prediction mode: off */ } if (get_bits1(&s->gb) != 0) { av_log(s->avctx, AV_LOG_ERROR, "PB frame mode no supported\n"); return -1; /* PB frame mode */ } /* skip unknown header garbage */ skip_bits(&s->gb, 41); s->qscale = get_bits(&s->gb, 5); skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */ /* 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; return 0; }