Function ff_ffv1_parse_header

libavcodec/ffv1_parse.c:208–443

}

int ff_ffv1_parse_header(FFV1Context *f, RangeCoder *c, uint8_t *state)
{
    if (f->version < 2) {
        int chroma_planes, chroma_h_shift, chroma_v_shift, transparency, colorspace, bits_per_raw_sample;
        unsigned v= ff_ffv1_get_symbol(c, state, 0);
        if (v >= 2) {
            av_log(f->avctx, AV_LOG_ERROR, "invalid version %d in ver01 header\n", v);
            return AVERROR_INVALIDDATA;
        }
        f->version = v;
        f->ac = ff_ffv1_get_symbol(c, state, 0);

        if (f->ac == AC_RANGE_CUSTOM_TAB) {
            for (int i = 1; i < 256; i++) {
                int st = ff_ffv1_get_symbol(c, state, 1) + c->one_state[i];
                if (st < 1 || st > 255) {
                    av_log(f->avctx, AV_LOG_ERROR, "invalid state transition %d\n", st);
                    return AVERROR_INVALIDDATA;
                }
                f->state_transition[i] = st;
            }
        } else {
            RangeCoder rc;
            ff_build_rac_states(&rc, 0.05 * (1LL << 32), 256 - 8);
            for (int i = 1; i < 256; i++)
                f->state_transition[i] = rc.one_state[i];
        }

        colorspace          = ff_ffv1_get_symbol(c, state, 0); //YUV cs type
        bits_per_raw_sample = f->version > 0 ? ff_ffv1_get_symbol(c, state, 0) : f->avctx->bits_per_raw_sample;
        chroma_planes       = get_rac(c, state);
        chroma_h_shift      = ff_ffv1_get_symbol(c, state, 0);
        chroma_v_shift      = ff_ffv1_get_symbol(c, state, 0);
        transparency        = get_rac(c, state);
        if (colorspace == 0 && f->avctx->skip_alpha)
            transparency = 0;

        if (f->plane_count) {
            if (colorspace          != f->colorspace                 ||
                bits_per_raw_sample != f->avctx->bits_per_raw_sample ||
                chroma_planes       != f->chroma_planes              ||
                chroma_h_shift      != f->chroma_h_shift             ||
                chroma_v_shift      != f->chroma_v_shift             ||
                transparency        != f->transparency) {
                av_log(f->avctx, AV_LOG_ERROR, "Invalid change of global parameters\n");
                return AVERROR_INVALIDDATA;
            }
        }

        if (chroma_h_shift > 4U || chroma_v_shift > 4U) {
            av_log(f->avctx, AV_LOG_ERROR, "chroma shift parameters %d %d are invalid\n",
                   chroma_h_shift, chroma_v_shift);
            return AVERROR_INVALIDDATA;
        }

        f->colorspace                 = colorspace;
        f->avctx->bits_per_raw_sample = bits_per_raw_sample;
        f->chroma_planes              = chroma_planes;