Skip to content
C99 library for fast image conversion between yuv420p and rgb24
C CMake
Branch: master
Clone or download
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
data fix test image Jun 11, 2017
.gitignore git ignore build folder Oct 12, 2017
CMakeLists.txt make ffmpeg dependency optional Dec 13, 2016
LICENSE Update name in license Feb 9, 2016
README.md update computation times in readme Sep 18, 2017
rgb.txt first commit Feb 8, 2016
rgba.txt add rgb32 to yuv420 function Dec 23, 2018
test_yuv_rgb.c add rgb32 to yuv420 function Dec 23, 2018
yuv_rgb.c add rgb32 to yuv420 function Dec 23, 2018
yuv_rgb.h add rgb32 to yuv420 function Dec 23, 2018

README.md

yuv2rgb

C library for fast image conversion between yuv420p and rgb24.

This is a simple library for optimized image conversion between YUV420p and rgb24. It was done mainly as an exercise to learn to use sse instrinsics, so there may still be room for optimization.

For each conversion, a standard c optimized function and two sse function (with aligned and unaligned memory) are implemented. The sse version requires only SSE2, which is available on any reasonnably recent CPU. The library also supports the three different YUV (YCrCb to be correct) color spaces that exist (see comments in code), and others can be added simply.

There is a simple test program, that convert a raw YUV file to rgb ppm format, and measure computation time. Optionnaly, it also compares the result and computation time with the ffmpeg implementation (that uses MMX), and with the IPP functions.

To compile, simply do :

mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make

The test program only support raw YUV files for the YUV420 format, and ppm for the RGB24 format. To generate a raw yuv file, you can use avconv:

avconv -i example.jpg -c:v rawvideo -pix_fmt yuv420p example.yuv

To generate the rgb file, you can use the ImageMagick convert program:

convert example.jpg example.ppm

Then, for YUV420 to RGB24 conversion, use the test program like that:

./test_yuv_rgb yuv2rgb image.yuv 4096 2160 image

The second and third parameters are image width and height (that are needed because not available in the raw YUV file), and fourth parameter is the output filename template (several output files will be generated, named for example output_sse.ppm, output_av.ppm, etc.)

Similarly, for RGB24 to YUV420 conversion:

./test_yuv_rgb yuv2rgb image.ppm image

On my computer, the test program on a 4K image give the following for yuv2rgb:

Time will be measured in each configuration for 100 iterations...
Processing time (std) : 2.630193 sec
Processing time (sse2_unaligned) : 0.704394 sec
Processing time (ffmpeg_unaligned) : 1.221432 sec
Processing time (ipp_unaligned) : 0.636274 sec
Processing time (sse2_aligned) : 0.606648 sec
Processing time (ffmpeg_aligned) : 1.227100 sec
Processing time (ipp_aligned) : 0.636951 sec

And for rgb2yuv:

Time will be measured in each configuration for 100 iterations...
Processing time (std) : 2.588675 sec
Processing time (sse2_unaligned) : 0.676625 sec
Processing time (ffmpeg_unaligned) : 3.385816 sec
Processing time (ipp_unaligned) : 0.593890 sec
Processing time (sse2_aligned) : 0.640630 sec
Processing time (ffmpeg_aligned) : 3.397952 sec
Processing time (ipp_aligned) : 0.579043 sec

configuration : gcc 4.9.2, swscale 3.0.0, IPP 9.0.1, intel i7-5500U

You can’t perform that action at this time.