[kodi-rpi] AC3 transcoding not working

[henkv]

AC3 transcoding is broken in kodi-rpi 20.2-5 aarch64. When I enable it the audo stops.
I don't know if it worked before. It's the first time I try it, but I know it works on Libreelec on the same hardware.

Hardware is a RPi 3b, Linux alarm 6.1.54-1-rpi-ARCH #1 SMP PREEMPT Tue Sep 19 11:55:52 MDT 2023 aarch64 GNU/Linux

The log does not give much information:
2023-10-01 16:40:29.320 T:419 debug <general>: CActiveAESink::OpenSink - ALSA Initialized:
2023-10-01 16:40:29.321 T:419 debug <general>: Output Device : vc4-hdmi (vc4hdmi)
2023-10-01 16:40:29.321 T:419 debug <general>: Sample Rate : 48000
2023-10-01 16:40:29.321 T:419 debug <general>: Sample Format : AE_FMT_S16NE
2023-10-01 16:40:29.321 T:419 debug <general>: Channel Count : 2
2023-10-01 16:40:29.321 T:419 debug <general>: Channel Layout: RAW, RAW
2023-10-01 16:40:29.321 T:419 debug <general>: Frames : 2400
2023-10-01 16:40:29.321 T:419 debug <general>: Frame Size : 4
2023-10-01 16:40:29.332 T:418 info <general>: CAEEncoderFFmpeg::Initialize - AC3 encoder ready
2023-10-01 16:40:29.366 T:418 debug <general>: CActiveAE::ClearDiscardedBuffers - buffer pool deleted
2023-10-01 16:40:30.377 T:418 info <general>: Skipped 3 duplicate messages..
2023-10-01 16:40:30.377 T:418 debug <general>: ActiveAE::SyncStream - average error 116.604984 above threshold of 100.000000
2023-10-01 16:40:30.428 T:418 debug <general>: ActiveAE::SyncStream - average error 20.604984 below threshold of 30.000000

[henkv]

One addition: Audio Passthrough works for AC3 encoded media. It's the transcoding of other media that doesn't work.

[graysky]

What version of ffmpeg is LE using that works for you? Just grep for it:

grep -i FFmpeg /path/to/kodi.log

[henkv]

LibreELEC:~ # grep -i FFmpeg .kodi/temp/kodi.log
2023-02-16 19:11:23.861 T:824 info <general>: FFmpeg version/source: 4.4.1-Kodi

[henkv]

Transcoding also works with kodi-rpi-git 21.x.63918.32d3bdf384-1

[root@alarm ~]# grep -i FFmpeg .kodi/temp/kodi.log
2023-09-28 04:40:42.005 T:333 info <general>: FFmpeg version/source: 6.0-Kodi

[graysky]

Thanks for confirming. Upstream uses 5.1.2-Nexus-Alpha3 of FFmpeg whereas I patched our package to use the official 5.1.3. The last release we had that used 4.4.1 like LE does was 20.1-4.
make_clickable_callback(MAGIC_URL_FULL, ' ', 'https://github.com/archlinuxarm/PKGBUILDs/tree/5d76ef67b7e52a1d9ada1cd1dcf5c8a56fbc0481/alarm/kodi-rpi', '', ' class="postlink"')

First thing to rule out an issue with 5.1.3. I need some time to work on that.

[henkv]

I downgraded to v20.1-4 and I can confirm that transcoding works with this version.

[graysky]

Please test this which is build using the same ffmpeg version as upstream rather than 5.1.3
make_clickable_callback(MAGIC_URL_FULL, '
', 'http://repo-ck.com/testing/', '', ' class="postlink"')make_clickable_callback(MAGIC_URL_FULL, '
', 'https://github.com/graysky2/PKGBUILDs/commit/bedd2baf217ab99994d0e7b443b5abddaaa6731b', '', ' class="postlink"')

[henkv]

Unfortunately, the issue still persists in this new version.

[henkv]

I recompiled kodi v20.2 with ffmpeg 4.4.1 and that also works. So it looks like there is an issue with ffmpeg 5.1