How to use encodeFromFd to replace encodeFromBuffer?

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
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1

Since the thread NvJPEGEncoder::encodeFromBuffer trigger segmentation fault is locked. I open this new thread.

I’ve tried the following code

    NvJPEGEncoder* jpegencoder = NvJPEGEncoder::createJPEGEncoder("jpegenc");
    NvBuffer bufferEnc(V4L2_PIX_FMT_YUV420M, roundedWidth, roundedHeight, 0);
    bufferEnc.allocateMemory();

    unsigned char* p_YEnc = bufferEnc.planes[0].data;
    unsigned char* p_UEnc = bufferEnc.planes[1].data;
    unsigned char* p_VEnc = bufferEnc.planes[2].data;
    err = cudaMemcpy2D(p_YEnc, roundedWidth, srcYPtr, 1920, roundedWidth, roundedHeight, cudaMemcpyHostToHost);
    err = cudaMemcpy2D(p_UEnc, roundedWidth/2, srcUPtr, 1920/2, roundedWidth/2, roundedHeight/2, cudaMemcpyHostToHost);
    err = cudaMemcpy2D(p_VEnc, roundedWidth/2, srcVPtr, 1920/2, roundedWidth/2, roundedHeight/2, cudaMemcpyHostToHost);
    
    unsigned char* outputBuf2 = outputBuf;
    unsigned long outputBufSize = sizeof(outputBuf);
    int ret = jpegencoder->encodeFromFd(bufferEnc.planes[0].fd, JCS_YCbCr, &outputBuf2, outputBufSize, 75);

and I got error:

[ERROR] (NvJpegEncoder.cpp:77) <jpegenc> Not encoding because fd = -1

But there seems no example showing me how to do a similar thing. Is there another example showing how to create a fd from some data in CPU?

3

Hi,
You would need to allocate NvBufSurface. It is demonstrated in 05_jpeg_encode. Please check the code of case 2.

4

Thank you,

I tried

    int roundedWidth = 250;
    int roundedHeight = 250;
    int roundedX1 = 1000;
    int roundedY1 = 250;

    NvBufSurfaceAllocateParams inputParams = {{0}};
    inputParams.params.width = roundedWidth;
    inputParams.params.height = roundedHeight;
    inputParams.params.layout = NVBUF_LAYOUT_PITCH;
    inputParams.params.colorFormat = NVBUF_COLOR_FORMAT_NV12;
    inputParams.params.memType = NVBUF_MEM_DEFAULT;
    inputParams.memtag = NvBufSurfaceTag_JPEG;
    NvBufSurface *nvbuf_surf = 0;
    int bufCreate = NvBufSurfaceAllocate(&nvbuf_surf, 1, &inputParams);
    printf("bufCreate: %d\n", bufCreate);
    

    NvJPEGEncoder* jpegencoder = NvJPEGEncoder::createJPEGEncoder("jpegenc");
    

    //copy data yuv to nvbuf_surf
    unsigned char* p_YNvBuf = (unsigned char*)nvbuf_surf->surfaceList[0].dataPtr;
    unsigned char* p_UNvBuf = (unsigned char*)nvbuf_surf->surfaceList[0].dataPtr + roundedWidth*roundedHeight;
    unsigned char* p_VNvBuf = (unsigned char*)nvbuf_surf->surfaceList[0].dataPtr + roundedWidth*roundedHeight*5/4;
    memset(p_YNvBuf, 0, roundedWidth*roundedHeight);
    
    p_YNvBuf[0]=0;
    p_YNvBuf[1]=0;
    p_YNvBuf[2]=0;
    
    nvbuf_surf->numFilled = 1;
    printf("nvbuf_surf->surfaceList[0].dataPtr: %p\n", nvbuf_surf->surfaceList[0].dataPtr);
    printf("nvbuf_surf->surfaceList[0].dataSize: %d\n", nvbuf_surf->surfaceList[0].dataSize);

    unsigned char* outputBuf2 = outputBuf;
    unsigned long outputBufSize = sizeof(outputBuf);
    int ret = jpegencoder->encodeFromFd(nvbuf_surf->surfaceList[0].bufferDesc, JCS_YCbCr, &outputBuf2, outputBufSize, 75);

But when I try to write data into surfaceList[0].dataPtr, no matter with memset or cudaMemcpy2D, I got a crash in encodeFromFd. Did I allocate correctly? Did I copy data correctly?

5

Hi,
NVBUF_COLOR_FORMAT_NV12 is a 2-surface format. If your data is in 3-plane Y, U and V, please allocate NVBUF_COLOR_FORMAT_YUV420. And please refer to read_dmabuf() in

/usr/src/jetson_multimedia_api/samples/common/classes/NvUtils.cpp

You would need to map the surface, synchronize it for CPU access, write data, and synchronize it for device access(hardware blocks such as VIC, NVENC).

6

Thank you.

Here is some working code. In case someone need it in the future.


    NvBufSurfaceAllocateParams inputParams = {{0}};
    inputParams.params.width = roundedWidth;
    inputParams.params.height = roundedHeight;
    inputParams.params.layout = NVBUF_LAYOUT_PITCH;
    inputParams.params.colorFormat = NVBUF_COLOR_FORMAT_YUV420;
    inputParams.params.memType = NVBUF_MEM_DEFAULT;
    inputParams.memtag = NvBufSurfaceTag_JPEG;
    NvBufSurface *nvbuf_surf = 0;
    int bufCreate = NvBufSurfaceAllocate(&nvbuf_surf, 1, &inputParams);
    printf("bufCreate: %d\n", bufCreate);

    int plane = 0;
    int retMap = NvBufSurfaceMap(nvbuf_surf, 0, plane, NVBUF_MAP_READ_WRITE);
    printf("NvBufSurfaceMap: %d\n", retMap);
    NvBufSurfaceSyncForCpu (nvbuf_surf, 0, plane);
    dstYPtr = (unsigned char*)nvbuf_surf->surfaceList->mappedAddr.addr[plane];
    err = cudaMemcpy2D(dstYPtr, nvbuf_surf->surfaceList->planeParams.pitch[plane], srcYPtr, 1920, roundedWidth, roundedHeight, cudaMemcpyHostToHost);
    retMap = NvBufSurfaceUnMap(nvbuf_surf, 0, plane);
    printf("NvBufSurfaceUnMap: %d\n", retMap);

    plane = 1;
    retMap = NvBufSurfaceMap(nvbuf_surf, 0, plane, NVBUF_MAP_READ_WRITE);
    printf("NvBufSurfaceMap: %d\n", retMap);
    NvBufSurfaceSyncForCpu (nvbuf_surf, 0, plane);
    dstUPtr = (unsigned char*)nvbuf_surf->surfaceList->mappedAddr.addr[plane];
    err = cudaMemcpy2D(dstUPtr, nvbuf_surf->surfaceList->planeParams.pitch[plane], srcUPtr, 1920/2, roundedWidth/2, roundedHeight/2, cudaMemcpyHostToHost);
    retMap = NvBufSurfaceUnMap(nvbuf_surf, 0, plane);
    printf("NvBufSurfaceUnMap: %d\n", retMap);

    plane = 2;
    retMap = NvBufSurfaceMap(nvbuf_surf, 0, plane, NVBUF_MAP_READ_WRITE);
    printf("NvBufSurfaceMap: %d\n", retMap);
    NvBufSurfaceSyncForCpu (nvbuf_surf, 0, plane);
    dstVPtr = (unsigned char*)nvbuf_surf->surfaceList->mappedAddr.addr[plane];
    err = cudaMemcpy2D(dstVPtr, nvbuf_surf->surfaceList->planeParams.pitch[plane], srcVPtr, 1920/2, roundedWidth/2, roundedHeight/2, cudaMemcpyHostToHost);
    retMap = NvBufSurfaceUnMap(nvbuf_surf, 0, plane);
    printf("NvBufSurfaceUnMap: %d\n", retMap);
8

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