# Video Encoder tests
The video encoder tests are a set of tests that validate various video encoding
scenarios. They are accompanied by the video encoder performance tests that can
be used to measure a video encoder's performance.
These tests run directly on top of the video encoder implementation, and
don't require the full Chrome browser stack. They are built on top of the
[GoogleTest](https://github.com/google/googletest/blob/main/README.md)
framework.
[TOC]
## Running from Tast
The Tast framework provides an easy way to run the video encoder tests from a
ChromeOS chroot. Test data is automatically deployed to the device being tested.
To run all video encoder tests use:
tast run $HOST video.EncodeAccel.*
Wildcards can be used to run specific sets of tests:
* Run all VP8 tests: `tast run $HOST video.EncodeAccel.vp8*`
Check the
[tast video folder](https://chromium.googlesource.com/chromiumos/platform/tast-tests/+/refs/heads/main/src/go.chromium.org/tast-tests/cros/local/bundles/cros/video/)
for a list of all available tests.
See the
[Tast quickstart guide](https://chromium.googlesource.com/chromiumos/platform/tast/+/HEAD/docs/quickstart.md)
for more information about the Tast framework.
## Running manually
To run the video encoder tests manually the _video_encode_accelerator_tests_
target needs to be built and deployed to the device being tested. Running
the video encoder tests can be done by executing:
./video_encode_accelerator_tests [<video path>]
e.g.: `./video_encode_accelerator_tests bear_320x192_40frames.yuv.webm`
Running the video encoder performance tests can be done in a smilar way by
building, deploying and executing the _video_encode_accelerator_perf_tests_
target.
./video_encode_accelerator_perf_tests [<video path>]
e.g.: `./video_encode_accelerator_perf_tests bear_320x192_40frames.yuv.webm`
__Test videos:__ Various test videos are present in the
[_media/test/data_](https://cs.chromium.org/chromium/src/media/test/data/)
folder in Chromium's source tree (e.g.
[_bear_320x192_40frames.yuv.webm_](https://cs.chromium.org/chromium/src/media/test/data/bear_320x192_40frames.yuv.webm)).
These videos are stored in compressed format and extracted at the start of each
test run, as storing uncompressed videos requires a lot of disk space. Currently
only VP9 or uncompressed videos are supported as test input. If no video is
specified _bear_320x192_40frames.yuv.webm_ will be used.
__Video Metadata:__ These videos also have an accompanying metadata _.json_ file
that needs to be deployed alongside the test video. The video metadata file is a
simple json file that contains info about the video such as its pixel format,
dimensions, framerate and number of frames. These can also be found in the
_media/test/data_ folder (e.g.
[_bear_320x192_40frames.yuv.webm.json_](https://cs.chromium.org/chromium/src/media/test/data/bear_320x192_40frames.yuv.webm.json)).
The metadata file must be _\<video path\>.json_ in the same directory.
## Command line options
Multiple command line arguments can be given to the command:
--codec codec profile to encode, "h264 (baseline)",
"h264main, "h264high", "vp8" and "vp9"
--output_folder overwrite the output folder used to store
performance metrics, if not specified results
will be stored in the current working directory.
-v enable verbose mode, e.g. -v=2.
--vmodule enable verbose mode for the specified module,
e.g. --vmodule=*media/gpu*=2.
--gtest_help display the gtest help and exit.
--help display this help and exit.
Non-performance tests only:
--num_temporal_layers the number of temporal layers of the encoded
bitstream. Only used in --codec=vp9 currently.
--disable_validator disable validation of encoded bitstream.
--output_bitstream save the output bitstream in either H264 AnnexB
format (for H264) or IVF format (for vp8 and
vp9) to <output_folder>/<testname>.
--output_images in addition to saving the full encoded,
bitstream it's also possible to dump individual
frames to <output_folder>/<testname>, possible
values are \"all|corrupt\"
--output_format set the format of images saved to disk,
supported formats are \"png\" (default) and
\"yuv\".
--output_limit limit the number of images saved to disk.
## Source code
See the video encoder tests [source code](https://cs.chromium.org/chromium/src/media/gpu/test/video_encode_accelerator_tests.cc).
See the video encoder performance tests [source code](https://cs.chromium.org/chromium/src/media/gpu/test/video_encode_accelerator_perf_tests.cc).
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