FFMpeg with X265

Question

I am currently trying to encode raw RGB24 images via x265. I already successfully did this with the x264 library, but a few things have changed as compared to the x265 library.

Here the problem in short: I want to convert the image I have from RGB24 to YUV 4:2:0 via the sws_scale function of FFMPEG. The prototype of the function is:

int sws_scale(SwsContext *c, uint8_t* src[], int srcStride[], int srcSliceY, int srcSliceH, uint8_t* dst[], int dstStride[])

Assuming image contains my raw image, srcstride and `m_height' the corresponding RGB stride and height of my image, I made the following call with x264

sws_scale(convertCtx, &image, &srcstride, 0, m_height, pic_in.img.plane, pic_in.img.i_stride);

pic_in is of type x264_picture_t which looks (brief) as follows

typedef struct
{
    ...
    x264_image_t img;

} x264_picture_t;

with x264_image_t

typedef struct
{
    ...
    int     i_stride[4];
    uint8_t *plane[4]; 

} x264_image_t;

Now, in x265 the structures have slightly changed to

typedef struct x265_picture
{
    ...
    void*   planes[3];
    int     stride[3];

} x265_picture;

And I am now not quite sure how to call the same function

sws_scale(convertCtx, &image, &srcstride, 0, m_height, ????, pic_in.stride);

I tried creating a temporary array, and then copying back and recasting the array items, but it doesnt seem to work

pic.planes[i] = reinterpret_cast<void*>(tmp[i]) ;

Can someone help me out?

Thanks a lot :)

Edit

I figured it out now

outputSlice = sws_scale(convertCtx, &image, &srcstride, 0, m_height, reinterpret_cast<uint8_t**>(pic_in.planes), pic_in.stride);

This seems to do the trick :)

And btw, for other people who are experiment with x265:in x264 there was a x264_picture_alloc function which I didn't manage to find in x265. So here is a function which I used in my application and which does the trick.

void x265_picture_alloc_custom( x265_picture *pic, int csp, int width, int height, uint32_t depth) {

    x265_picture_init(&mParam, pic);

    pic->colorSpace = csp;
    pic->bitDepth = depth;
    pic->sliceType = X265_TYPE_AUTO;

    uint32_t pixelbytes = depth > 8 ? 2 : 1;
    uint32_t framesize = 0;

    for (int i = 0; i < x265_cli_csps[csp].planes; i++)
    {
        uint32_t w = width >> x265_cli_csps[csp].width[i];
        uint32_t h = height >> x265_cli_csps[csp].height[i];
        framesize += w * h * pixelbytes;
    }

    pic->planes[0] = new char[framesize];
    pic->planes[1] = (char*)(pic->planes[0]) + width * height * pixelbytes;
    pic->planes[2] = (char*)(pic->planes[1]) + ((width * height * pixelbytes) >> 2);

    pic->stride[0] = width;
    pic->stride[1] = pic->stride[2] = pic->stride[0] >> 1;

}

luca luca · Accepted Answer · 2014-03-03T14:38:35

And I am now not quite sure how to call the same function

sws_scale(convertCtx, &image, &srcstride, 0, m_height, ????, pic_in.stride);

tried with?:

 sws_scale(convertCtx, &image, &srcstride, 0, m_height, pic_in.planes,pic_in.stride);

what error do you have? have you initialized memory of x265_picture?

FFMpeg with X265

1 Answers