Est-ce que quelqu'un a un exemple de code pour le traitement de vImage sur iOS?

Question

J'ai lu tous les documents que je peux trouver, mais je n'arrive pas à obtenir un simple appel de vImage. J'ai juste besoin d'un vrai exemple. La documentation est très clairsemée.

Answer 1

La documentation n'existe pas car les bibliothèques vImage ne sont pas disponibles sur iOS.

vImage est disponible sur iOS depuis la version 5.0. The documentation is here.

Answer 2

Mise à jour de la réponse d'Ole Bermann: le framework Accelerate a été ajouté dans iOS 5.0.

Answer 3

Si vous traitez la vidéo en temps réel, et votre entrée est traitée dans un tampon de pixel, voici comment copier ce tampon dans un vImage, à quel point vous pouvez appeler ce que vous des commandes comme:

- (CVPixelBufferRef)copyRenderedPixelBuffer:(CVPixelBufferRef)pixelBuffer 
{ 
    CVPixelBufferLockBaseAddress(pixelBuffer, 0); 

    // vImage processing 
    vImage_Error err; 
    vImage_Buffer buffer; 
    buffer.data = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer); 
    buffer.rowBytes = CVPixelBufferGetBytesPerRow(pixelBuffer); 
    buffer.width = CVPixelBufferGetWidth(pixelBuffer); 
    buffer.height = CVPixelBufferGetHeight(pixelBuffer); 
    vImageCVImageFormatRef vformat = vImageCVImageFormat_CreateWithCVPixelBuffer(pixelBuffer); 
    vImage_CGImageFormat cgformat = { 
     .bitsPerComponent = 8, 
     .bitsPerPixel = 32, 
     .bitmapInfo = kCGBitmapByteOrderDefault, 
     .colorSpace = NULL, //sRGB 
    }; 
    const CGFloat bgColor[3] = {0.0, 0.0, 0.0}; 
    vImageBuffer_InitWithCVPixelBuffer(&buffer, &cgformat, pixelBuffer, vformat, bgColor, kvImageNoAllocate); 

    vImage_Buffer outbuffer; 
    void *tempBuffer; 
    tempBuffer = malloc(CVPixelBufferGetBytesPerRow(pixelBuffer) * CVPixelBufferGetHeight(pixelBuffer)); 
    outbuffer.data = tempBuffer; 
    outbuffer.rowBytes = CVPixelBufferGetBytesPerRow(pixelBuffer); 
    outbuffer.width = CVPixelBufferGetWidth(pixelBuffer); 
    outbuffer.height = CVPixelBufferGetHeight(pixelBuffer); 

    err = vImageEqualization_ARGB8888(&buffer, &outbuffer, kvImageNoFlags); 

    if(err != -1) 
     err = vImageContrastStretch_ARGB8888(&buffer, &outbuffer, kvImageNoFlags); 

    if(err != -1) 
     err = vImageBuffer_CopyToCVPixelBuffer(&outbuffer, &cgformat, pixelBuffer, vformat, bgColor, kvImageNoFlags); 

    if(err != -1) 
     free(tempBuffer); 

    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0); 

    return (CVPixelBufferRef)CFRetain(pixelBuffer); 
} 

Answer 4

Un exemple encore plus avancé, avec l'optimisation des fonctions d'égalisation et d'étirement (ignorer en commentaire le code, mais vous pouvez l'utiliser-il fonctionne aussi:

- (CVPixelBufferRef)copyRenderedPixelBuffer:(CVPixelBufferRef)pixelBuffer { 

CVPixelBufferLockBaseAddress(pixelBuffer, 0); 

unsigned char *base = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer); 
size_t width = CVPixelBufferGetWidth(pixelBuffer); 
size_t height = CVPixelBufferGetHeight(pixelBuffer); 
size_t stride = CVPixelBufferGetBytesPerRow(pixelBuffer); 

vImage_Buffer _img = { 
    .data = base, 
    .height = height, 
    .width = width, 
    .rowBytes = stride 
}; 

vImage_Error err; 
vImage_Buffer _dstA, _dstR, _dstG, _dstB; 

err = vImageBuffer_Init(&_dstA, height, width, 8 * sizeof(uint8_t), kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageBuffer_Init (alpha) error: %ld", err); 

err = vImageBuffer_Init(&_dstR, height, width, 8 * sizeof(uint8_t), kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageBuffer_Init (red) error: %ld", err); 

err = vImageBuffer_Init(&_dstG, height, width, 8 * sizeof(uint8_t), kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageBuffer_Init (green) error: %ld", err); 

err = vImageBuffer_Init(&_dstB, height, width, 8 * sizeof(uint8_t), kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageBuffer_Init (blue) error: %ld", err); 

err = vImageConvert_ARGB8888toPlanar8(&_img, &_dstA, &_dstR, &_dstG, &_dstB, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageConvert_ARGB8888toPlanar8 error: %ld", err); 

err = vImageEqualization_Planar8(&_dstR, &_dstR, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageEqualization_Planar8 (red) error: %ld", err); 

err = vImageEqualization_Planar8(&_dstG, &_dstG, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageEqualization_Planar8 (green) error: %ld", err); 

err = vImageEqualization_Planar8(&_dstB, &_dstB, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageEqualization_Planar8 (blue) error: %ld", err); 

err = vImageConvert_Planar8toARGB8888(&_dstA, &_dstR, &_dstG, &_dstB, &_img, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImageConvert_Planar8toARGB8888 error: %ld", err); 

err = vImageContrastStretch_ARGB8888(&_img, &_img, kvImageNoError); 
if (err != kvImageNoError) 
    NSLog(@"vImageContrastStretch_ARGB8888 error: %ld", err); 

err = vImagePermuteChannels_ARGB8888(&_img, &_img, map, kvImageNoFlags); 
if (err != kvImageNoError) 
    NSLog(@"vImagePermuteChannels_ARGB8888 error: %ld", err); 

free(_dstA.data); 
free(_dstR.data); 
free(_dstG.data); 
free(_dstB.data); 

CVPixelBufferUnlockBaseAddress(pixelBuffer, 0); 

return (CVPixelBufferRef)CFRetain(pixelBuffer); 

}