Function decode_chunks

libavcodec/mpeg12dec.c:2238–2554

}

static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
                         int *got_output, const uint8_t *buf, int buf_size)
{
    Mpeg1Context *s = avctx->priv_data;
    MPVContext *const s2 = &s->slice.c;
    const uint8_t *buf_ptr = buf;
    const uint8_t *buf_end = buf + buf_size;
    int ret, input_size;
    int last_code = 0, skip_frame = 0;
    int picture_start_code_seen = 0;

    for (;;) {
        /* find next start code */
        uint32_t start_code = -1;
        buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &start_code);
        if (start_code > 0x1ff) {
            if (!skip_frame) {
                mpeg12_execute_slice_threads(avctx, s);

                ret = slice_end(avctx, picture, got_output);
                if (ret < 0)
                    return ret;
            }
            s2->pict_type = 0;

            if (avctx->err_recognition & AV_EF_EXPLODE && s2->er.error_count)
                return AVERROR_INVALIDDATA;

            return FFMAX(0, buf_ptr - buf);
        }

        input_size = buf_end - buf_ptr;

        if (avctx->debug & FF_DEBUG_STARTCODE)
            av_log(avctx, AV_LOG_DEBUG, "%3"PRIX32" at %td left %d\n",
                   start_code, buf_ptr - buf, input_size);

        /* prepare data for next start code */
        switch (start_code) {
        case SEQ_START_CODE:
            if (last_code == 0) {
                mpeg1_decode_sequence(avctx, buf_ptr, input_size);
                if (buf != avctx->extradata)
                    s->sync = 1;
            } else {
                av_log(avctx, AV_LOG_ERROR,
                       "ignoring SEQ_START_CODE after %X\n", last_code);
                if (avctx->err_recognition & AV_EF_EXPLODE)
                    return AVERROR_INVALIDDATA;
            }
            break;

        case PICTURE_START_CODE:
            if (picture_start_code_seen && s2->picture_structure == PICT_FRAME) {
               /* If it's a frame picture, there can't be more than one picture header.
                  Yet, it does happen and we need to handle it. */
               av_log(avctx, AV_LOG_WARNING, "ignoring extra picture following a frame-picture\n");
               break;