static int cinaudio_decode_frame(AVCodecContext *avctx,
                                 void *data, int *data_size,
                                 AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    CinAudioContext *cin = avctx->priv_data;
    const uint8_t *src = buf;
    int16_t *samples = data;
    int delta;

    buf_size = FFMIN(buf_size, *data_size/2);

    delta = cin->delta;
    if (cin->initial_decode_frame) {
        cin->initial_decode_frame = 0;
        delta = (int16_t)AV_RL16(src); src += 2;
        *samples++ = delta;
        buf_size -= 2;
    }
    while (buf_size > 0) {
        delta += cinaudio_delta16_table[*src++];
        delta = av_clip_int16(delta);
        *samples++ = delta;
        --buf_size;
    }
    cin->delta = delta;

    *data_size = (uint8_t *)samples - (uint8_t *)data;

    return src - buf;
}