Function decode_nal_units

libavcodec/h264.c:2715–2930

static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
    MpegEncContext * const s = &h->s;
    AVCodecContext * const avctx= s->avctx;
    int buf_index=0;
    H264Context *hx; ///< thread context
    int context_count = 0;
    int next_avc= h->is_avc ? 0 : buf_size;

    h->max_contexts = avctx->thread_count;
#if 0
    int i;
    for(i=0; i<50; i++){
        av_log(NULL, AV_LOG_ERROR,"%02X ", buf[i]);
    }
#endif
    if(!(s->flags2 & CODEC_FLAG2_CHUNKS)){
        h->current_slice = 0;
        if (!s->first_field)
            s->current_picture_ptr= NULL;
        ff_h264_reset_sei(h);
    }

    for(;;){
        int consumed;
        int dst_length;
        int bit_length;
        const uint8_t *ptr;
        int i, nalsize = 0;
        int err;

        if(buf_index >= next_avc) {
            if(buf_index >= buf_size) break;
            nalsize = 0;
            for(i = 0; i < h->nal_length_size; i++)
                nalsize = (nalsize << 8) | buf[buf_index++];
            if(nalsize <= 1 || nalsize > buf_size - buf_index){
                if(nalsize == 1){
                    buf_index++;
                    continue;
                }else{
                    av_log(h->s.avctx, AV_LOG_ERROR, "AVC: nal size %d\n", nalsize);
                    break;
                }
            }
            next_avc= buf_index + nalsize;
        } else {
            // start code prefix search
            for(; buf_index + 3 < next_avc; buf_index++){
                // This should always succeed in the first iteration.
                if(buf[buf_index] == 0 && buf[buf_index+1] == 0 && buf[buf_index+2] == 1)
                    break;
            }

            if(buf_index+3 >= buf_size) break;

            buf_index+=3;
            if(buf_index >= next_avc) continue;
        }