static int cavs_decode_frame(AVCodecContext * avctx,void *data, int *data_size,

                             AVPacket *avpkt) {

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    AVSContext *h = avctx->priv_data;

    MpegEncContext *s = &h->s;

    int input_size;

    const uint8_t *buf_end;

    const uint8_t *buf_ptr;

    AVFrame *picture = data;

    uint32_t stc = -1;



    s->avctx = avctx;



    if (buf_size == 0) {

        if (!s->low_delay && h->DPB[0].f.data[0]) {

            *data_size = sizeof(AVPicture);

            *picture = *(AVFrame *) &h->DPB[0];

        }

        return 0;

    }



    buf_ptr = buf;

    buf_end = buf + buf_size;

    for(;;) {

        buf_ptr = ff_find_start_code(buf_ptr,buf_end, &stc);

        if(stc & 0xFFFFFE00)

            return FFMAX(0, buf_ptr - buf - s->parse_context.last_index);

        input_size = (buf_end - buf_ptr)*8;

        switch(stc) {

        case CAVS_START_CODE:

            init_get_bits(&s->gb, buf_ptr, input_size);

            decode_seq_header(h);

            break;

        case PIC_I_START_CODE:

            if(!h->got_keyframe) {

                if(h->DPB[0].f.data[0])

                    avctx->release_buffer(avctx, (AVFrame *)&h->DPB[0]);

                if(h->DPB[1].f.data[0])

                    avctx->release_buffer(avctx, (AVFrame *)&h->DPB[1]);

                h->got_keyframe = 1;

            }

        case PIC_PB_START_CODE:

            *data_size = 0;

            if(!h->got_keyframe)

                break;

            init_get_bits(&s->gb, buf_ptr, input_size);

            h->stc = stc;

            if(decode_pic(h))

                break;

            *data_size = sizeof(AVPicture);

            if(h->pic_type != AV_PICTURE_TYPE_B) {

                if(h->DPB[1].f.data[0]) {

                    *picture = *(AVFrame *) &h->DPB[1];

                } else {

                    *data_size = 0;

                }

            } else

                *picture = *(AVFrame *) &h->picture;

            break;

        case EXT_START_CODE:

            

            break;

        case USER_START_CODE:

            

            break;

        default:

            if (stc <= SLICE_MAX_START_CODE) {

                init_get_bits(&s->gb, buf_ptr, input_size);

                decode_slice_header(h, &s->gb);

            }

            break;

        }

    }

}
