Combining two YV12 image buffers into a single side-by-side image

问题

I have two image buffers in YV12 format that I need to combine into a single side-by-side image.

(1920x1080) + (1920x1080) = (3840*1080)

YV12 is split into 3 seperate planes.

YYYYYYYY VV UU

The pixel format is 12 bits-per-pixel.

I have created a method that memcpys one buffer (1920x1080) into a larger buffer (3840x1080), but it isn't working.

Here is my c++.

BYTE* source = buffer;
BYTE* destination = convertBuffer3D;

// copy over the Y
for (int x = 0; x < height; x++)
{
    memcpy(destination, source, width);
    destination += width * 2;
    source += width;
}

// copy over the V
for (int x = 0; x < (height / 2); x++)
{
    memcpy(destination, source, width / 2);
    destination += width;
    source += width / 2;
}

// copy over the U
for (int x = 0; x < (height / 2); x++)
{
    memcpy(destination, source, width / 2);
    destination += width;
    source += width / 2;
}

I expected this:

Instead, I get this result:

What am I missing?

回答1:

What you wanted is this:

Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
U1 U1 U2 U2 V1 V1 V2 V2
U1 U1 U2 U2 V1 V1 V2 V2

but your code is actually doing this:

Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
Y1 Y1 Y1 Y1 Y2 Y2 Y2 Y2
U1 U1 V1 V1 U2 U2 V2 V2
U1 U1 V1 V1 U2 U2 V2 V2

Here's the corrected code (untested)

BYTE* source = buffer;
BYTE* destination = convertBuffer3D;

// copy over the Y
for (int x = 0; x < height; x++)
{
    memcpy(destination, source, width);
    destination += width * 2;
    source += width;
}

for (int x = 0; x < (height / 2); x++)
{
    // copy over the V
    memcpy(destination, source, width / 2);
    destination += width;
    source += width / 2;

    // copy over the U
    memcpy(destination, source, width / 2);
    destination += width;
    source += width / 2;
}

来源：https://stackoverflow.com/questions/38404312/combining-two-yv12-image-buffers-into-a-single-side-by-side-image

标签

c++

yuv

color-space