VDAtest (or video_decode_accelerator_unittest
) and VEAtest (or video_encode_accelerator_unittest
) are unit tests that embeds the Chrome video decoding/encoding stack without requiring the whole browser, meaning they can work in a headless environment. They includes a variety of tests to validate the decoding and encoding stacks with h264, vp8 and vp9.
Running these tests manually can be very useful when bringing up a new codec, or in order to make sure that new code does not break hardware decoding and/or encoding. This document is a walk though the prerequisites for running these programs, as well as their most common options.
The required kernel drivers should be loaded, and there should exist a /dev/video-dec0
symbolic link pointing to the decoder device node (e.g. /dev/video-dec0
→ /dev/video0
). Similarly, a /dev/video-enc0
symbolic link should point to the encoder device node.
The unittests can be built by specifying the video_decode_accelerator_unittest
and video_encode_accelerator_unittest
targets to ninja
. If you are building for an ARM board that is not yet supported by the simplechrome workflow, use arm-generic
as the board. It should work across all ARM targets.
For unlisted Intel boards, any other Intel target (preferably with the same chipset) should be usable with libva. AMD targets can use amd64-generic
.
The media/test/data
folder in Chromium's source tree contains files with encoded video data (test-25fps.h264
, test-25fps.vp8
and test-25fps.vp9
). Each of these files also has a .md5
counterpart, which contains the md5 checksums of valid thumbnails.
Running the VDAtest can be done as follows:
./video_decode_accelerator_unittest --disable_rendering --single-process-tests --test_video_data=test_video
Where test_video is of the form
filename:width:height:numframes:numfragments:minFPSwithRender:minFPSnoRender:profile
The correct value of test_video for each test file follows:
test-25fps.h264:320:240:250:258:35:150:1
test-25fps.vp8:320:240:250:250:35:150:11
test-25fps.vp9:320:240:250:250:35:150:12
So in order to run all h264 tests, one would invoke
./video_decode_accelerator_unittest --disable_rendering --single-process-tests --test_video_data=test-25fps.h264:320:240:250:258:35:150:1
./video_decode_accelerator_unittest --help
will list all valid options.
The list of available tests can be retrieved using the --gtest_list_tests
option.
By default, all tests are run, which can be a bit too much, especially when bringing up a new codec. The --gtest_filter
option can be used to specify a pattern of test names to run. For instance, to only run the TestDecodeTimeMedian
test, one can specify --gtest_filter="*TestDecodeTimeMedian*"
.
So the complete command line to test vp9 decoding with the TestDecodeTimeMedian
test only (a good starting point for bringup) would be
./video_decode_accelerator_unittest --disable_rendering --single-process-tests --test_video_data=test-25fps.vp9:320:240:250:250:35:150:12 --gtest_filter="*TestDecodeTimeMedian*"
The --vmodule
options allows to specify a set of source files that should be more verbose about what they are doing. For basic usage, a useful set of vmodule options could be:
--vmodule=*/media/gpu/*=4
Use the --disable_rendering --rendering_fps=0 --gtest_filter="DecodeVariations/*/0"
options to max the decoder output and measure its performance.
Use --gtest_filter="ResourceExhaustion*/0"
to run 3 decoders in parallel, and --gtest_filter="ResourceExhaustion*/1"
to run 4 decoders in parallel.
Using all these options together, we can invoke VDAtest in the following way for a verbose H264 decoding test:
./video_decode_accelerator_unittest --single-process-tests --disable_rendering --gtest_filter="*TestDecodeTimeMedian*" --vmodule=*/media/gpu/*=4 --test_video_data=test-25fps.h264:320:240:250:258:35:150:1
The VEA works in a similar fashion to the VDA, taking raw YUV files in I420 format as input and producing e.g. a H.264 Annex-B byte stream. Sample raw YUV files can be found at the following locations:
It is recommended to rename these files after downloading them to e.g. crowd1080.yuv
and bear-320x180.yuv
.
The VEA can then be tested as follows:
./video_encode_accelerator_unittest --single-process-tests --disable_flush --gtest_filter=SimpleEncode/VideoEncodeAcceleratorTest.TestSimpleEncode/0 --test_stream_data=bear-320x180.yuv:320:180:1:bear.mp4:100000:30
for the bear
file, and
./video_encode_accelerator_unittest --single-process-tests --disable_flush --gtest_filter=SimpleEncode/VideoEncodeAcceleratorTest.TestSimpleEncode/0 --test_stream_data=crowd1080.yuv:1920:1080:1:crowd.mp4:4000000:30
for the larger crowd
file. These commands will put the encoded output into bear.mp4
and crowd.mp4
respectively. They can then be copied on the host and played with mplayer -fps 25
.
The VDAtest's source code can be consulted here: https://cs.chromium.org/chromium/src/media/gpu/video_decode_accelerator_unittest.cc.
V4L2 support: https://cs.chromium.org/chromium/src/media/gpu/v4l2/.
VAAPI support: https://cs.chromium.org/chromium/src/media/gpu/vaapi/.