static int msrle_decode_frame(AVCodecContext *avctx,

                              void *data, int *data_size,

                              AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    MsrleContext *s = avctx->priv_data;

    int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;



    s->buf = buf;

    s->size = buf_size;



    s->frame.reference = 3;

    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;

    if (avctx->reget_buffer(avctx, &s->frame)) {

        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

        return -1;

    }



    if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {

        const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);



        if (pal) {

            s->frame.palette_has_changed = 1;

            memcpy(s->pal, pal, AVPALETTE_SIZE);

        }

    }



    /* make the palette available */

    memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);



    /* FIXME how to correctly detect RLE ??? */

    if (avctx->height * istride == avpkt->size) { /* assume uncompressed */

        int linesize = (avctx->width * avctx->bits_per_coded_sample + 7) / 8;

        uint8_t *ptr = s->frame.data[0];

        uint8_t *buf = avpkt->data + (avctx->height-1)*istride;

        int i, j;



        for (i = 0; i < avctx->height; i++) {

            if (avctx->bits_per_coded_sample == 4) {

                for (j = 0; j < avctx->width - 1; j += 2) {

                    ptr[j+0] = buf[j>>1] >> 4;

                    ptr[j+1] = buf[j>>1] & 0xF;

                }

                if (avctx->width & 1)

                    ptr[j+0] = buf[j>>1] >> 4;

            } else {

                memcpy(ptr, buf, linesize);

            }

            buf -= istride;

            ptr += s->frame.linesize[0];

        }

    } else {

        bytestream2_init(&s->gb, buf, buf_size);

        ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);

    }



    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = s->frame;



    /* report that the buffer was completely consumed */

    return buf_size;

}
