static int cdxl_decode_frame(AVCodecContext *avctx, void *data,
                             int *data_size, AVPacket *pkt)
{
    CDXLVideoContext *c = avctx->priv_data;
    AVFrame * const p = &c->frame;
    int ret, w, h, encoding, format, buf_size = pkt->size;
    const uint8_t *buf = pkt->data;

    if (buf_size < 32)
        return AVERROR_INVALIDDATA;
    encoding        = buf[1] & 7;
    format          = buf[1] & 0xE0;
    w               = AV_RB16(&buf[14]);
    h               = AV_RB16(&buf[16]);
    c->bpp          = buf[19];
    c->palette_size = AV_RB16(&buf[20]);
    c->palette      = buf + 32;
    c->video        = c->palette + c->palette_size;
    c->video_size   = buf_size - c->palette_size - 32;

    if (c->palette_size > 512)
        return AVERROR_INVALIDDATA;
    if (buf_size < c->palette_size + 32)
        return AVERROR_INVALIDDATA;
    if (c->bpp < 1)
        return AVERROR_INVALIDDATA;
    if (c->bpp > 8) {
        av_log_ask_for_sample(avctx, "unsupported pixel size: %d\n", c->bpp);
        return AVERROR_PATCHWELCOME;
    }
    if (format) {
        av_log_ask_for_sample(avctx, "unsupported pixel format: %d\n", format);
        return AVERROR_PATCHWELCOME;
    }

    if ((ret = av_image_check_size(w, h, 0, avctx)) < 0)
        return ret;
    if (w != avctx->width || h != avctx->height)
        avcodec_set_dimensions(avctx, w, h);

    if (c->video_size < FFALIGN(avctx->width, 16) * avctx->height * c->bpp / 8)
        return AVERROR_INVALIDDATA;
    if (!encoding && c->palette_size && c->bpp <= 8) {
        avctx->pix_fmt = PIX_FMT_PAL8;
    } else if (encoding == 1 && (c->bpp == 6 || c->bpp == 8)) {
        if (c->palette_size != (1 << (c->bpp - 1)))
            return AVERROR_INVALIDDATA;
        avctx->pix_fmt = PIX_FMT_BGR24;
    } else {
        av_log_ask_for_sample(avctx, "unsupported encoding %d and bpp %d\n",
                              encoding, c->bpp);
        return AVERROR_PATCHWELCOME;
    }

    if (p->data[0])
        avctx->release_buffer(avctx, p);

    p->reference = 0;
    if ((ret = avctx->get_buffer(avctx, p)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return ret;
    }
    p->pict_type = AV_PICTURE_TYPE_I;

    if (encoding) {
        av_fast_padded_malloc(&c->new_video, &c->new_video_size,
                              h * w + FF_INPUT_BUFFER_PADDING_SIZE);
        if (!c->new_video)
            return AVERROR(ENOMEM);
        if (c->bpp == 8)
            cdxl_decode_ham8(c);
        else
            cdxl_decode_ham6(c);
    } else {
        cdxl_decode_rgb(c);
    }
    *data_size      = sizeof(AVFrame);
    *(AVFrame*)data = c->frame;

    return buf_size;
}