AVIF encoder fails when reused

[Wmeeww]

When i try to encode a same image but with new pixels and using the encoder cached on header, it fails at result = avifEncoderWrite(encoder, image, &avifOutput);

with error: AVIF_RESULT_ENCODE_COLOR_FAILED

Is it not possible to reutilize the encoder/image?

avifEncoder* encoder      = nullptr;
avifImage*   image        = nullptr;
avifRGBImage avifRgb      = {};
avifRWData   avifOutput   = AVIF_DATA_EMPTY; 

void initializeAVIF()
{
    encoder = avifEncoderCreate();
    if (!encoder)
    {
		std::cerr << "Failed to create AVIF encoder" << std::endl;
		return;
    }

    encoder->maxThreads   = std::thread::hardware_concurrency();  // Adjust based on your needs
    encoder->speed        = 10; // Fastest encoding (0 = slowest/best, 10 = fastest)
    encoder->minQuantizer = 30; // Higher = more compression/lower quality
    encoder->maxQuantizer = 30; // Keep both quantizers equal for consistent quality
    
    image = avifImageCreate(width, height, 8, AVIF_PIXEL_FORMAT_YUV444);
	if (!image)
	{
		std::cerr << "Failed to create AVIF image" << std::endl;
		avifEncoderDestroy(encoder);
		return;
	}

    // Configure image properties
    image->colorPrimaries          = AVIF_COLOR_PRIMARIES_BT709;
    image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_SRGB;
    image->matrixCoefficients      = AVIF_MATRIX_COEFFICIENTS_BT601;

    // Set up RGB image
    avifRGBImageSetDefaults(&avifRgb, image);
    avifRgb.format   = AVIF_RGB_FORMAT_RGB;
    avifRgb.depth    = 8;
    avifRgb.pixels   = Scan0;
    avifRgb.rowBytes = stride;

    // Update RGB to YUV conversion
    auto result = avifImageRGBToYUV(image, &avifRgb);
    if (result != AVIF_RESULT_OK)
    {
        std::cerr << "RGB to YUV conversion failed: " << avifResultToString(result) << std::endl;
        return false;
    }
}

bool encodeAVIF()
{
    if (!encoder || !image)
        return false;

    // Encode the image
    result = avifEncoderWrite(encoder, image, &avifOutput);
    if (result != AVIF_RESULT_OK)
    {
        avifImageDestroy(image);
        avifEncoderDestroy(encoder);
        return false;
    }

    websocketpp::lib::error_code ec;
    wsClient.send(connection, avifOutput.data, avifOutput.size,  websocketpp::frame::opcode::binary, ec);

    // Cleanup
    avifRWDataFree(&avifOutput);
    //avifImageDestroy(image);

    return true;
}

[y-guyon]

Thank you for your interest in libavif.

Unfortunately an avifEncoder instance cannot be reused for encoding multiple still images or animations.
Please call avifEncoderCreate() for each asset to encode and remember to call avifEncoderDestroy() as many times as avifEncoderCreate().