4.9. Android Multimedia (Video encode/decode)

This application note describes video decoding/encoding using the onboard Wave5 chip found in the Texas Instruments AM62Px SoC.

The Wave5 hardware is implemented via:

the wave5 driver, located in ~/10_00_00/ti-kernel-aosp/common/drivers/media/platform/chips-media/wave5/
a firmware located in ~/10_00_00/ti-aosp-14/vendor/ti/vendor/ti/am62x/firmware/vendor/firmware/cnm/

The userspace associated component is based on the AOSP-provided v4l2_codec2 HAL. The source can be found in ~/10_00_00/ti-aosp-14/external/v4l2_codec2.

4.9.1. Testing

4.9.1.1. Using `atest`

Android provides all kind of tests to test the media framework. We can run a sample playback via atest from a development tree.

# Standard Android build commands
$ cd ${YOUR_PATH}/ti-aosp-14
$ source build/envsetup.sh
$ lunch <BUILD_TARGET>

# install the required media files, downloads from network
$ cts/tests/tests/media/player/
$ ./copy_media.sh
$ cd -

# run the playback test
$ atest android.media.player.cts.MediaPlayerTest#testLocalVideo_MP4_H264_480x360_500kbps_25fps_AAC_Stereo_128kbps_44110Hz

4.9.1.2. Using Gallery

To play test videos, we can also use the Gallery app.

First, download the Big Buck Bunny test videos:

# 1080p, 60FPS, h264
$ wget http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_60fps_normal.mp4

# 4k, 30FPS, h264
$ wget http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_2160p_30fps_normal.mp4

Then, push them in the Movies folder:

$ adb push bbb_sunflower_1080p_60fps_normal.mp4 /sdcard/Movies
$ adb push bbb_sunflower_2160p_30fps_normal.mp4 /sdcard/Movies

Finally, reboot the board:

$ adb reboot

Then run the Gallery app from the UI and play the videos.

4.9.1.3. Using `screenrecord`

To test video encoding, we can use the screenrecord command.

$ adb root
$ adb shell 'screenrecord /data/screenrecord.mp4' # Do some screen activity, then hit Ctrl-C
$ adb pull /data/screenrecord.mp4

Tip

screenrecord only records frames when there is some user activity detected. Make sure to generate some activity to avoid empty video files.

4.9.2. Debugging tips

4.9.2.1. List available codecs

dumpsys can be used to list the available codecs on an Android system. To check that the v4l2 codecs are available, run:

$ adb shell dumpsys media.player | grep -A 10 v4l2
   Decoder "c2.v4l2.avc.decoder" supports
     aliases: []
     attributes: 0xa: [
       encoder: 0,
       vendor: 1,
       software-only: 0,
       hw-accelerated: 1 ]
     owner: "codec2::default"
     rank: 128
     profile/levels: [
           1/65536 (Baseline/5.2),
 --
   Decoder "c2.v4l2.hevc.decoder" supports
     aliases: []
     attributes: 0xa: [
       encoder: 0,
       vendor: 1,
       software-only: 0,
       hw-accelerated: 1 ]
     owner: "codec2::default"
     rank: 128
     profile/levels: [
           1/524288 (Main/High 5.2),
 --
   Encoder "c2.v4l2.avc.encoder" supports
     aliases: []
     attributes: 0xb: [
       encoder: 1,
       vendor: 1,
       software-only: 0,
       hw-accelerated: 1 ]
     owner: "codec2::default"
     rank: 128
     profile/levels: [
           1/32768 (Baseline/5.1),

4.9.2.2. Verbose logcat logging

The logs in logcat from v4l2_codec2 are not very verbose by default. To enable more logs, v4l2_codec2 should be rebuild. It’s possible to enable all logs with:

$ cd ~/src/ti-aosp-14/external/v4l2_codec2
$ sed -i 's#//\#define LOG_NDEBUG 0#\#define LOG_NDEBUG 0#' *.cpp