RP2 multichannel FLAC playback

Help and Support Raspberry Pi
1

Hello,

I have an issue with the multichannel FLAC playback because of the frequent dropouts. I experienced this problem with multiple 5.1 channel 24 bit 88.2-96KHz album and also with some stereo FLACS but very rarely.

I found a similar issue here and I tried the suggested “hdmi_mai_thresh=0x1412” setting, but unfortunately does not solved my issue.

I am using the latest OSMC version on a RP2.

Could anybody help me to solve this issue?
Regards,
Peter

2

You’ll need updated firmware. Hopefully it will be included in next OSMC update.

You can download these:

and replace the files on the boot partition of your sdcard.

3

Sorry, but I have not so much time to test the new firmware, but as I see unfortunately that is still exits with a 192Khz stereo FLAC title… (but I tested over network connection)

4

The updated firmware won’t help network issues. Would be useful if you could try local playback (sdcard or usb stick) to rule out the network.
buffermode=1 may be worth trying if it is the network. See: http://kodi.wiki/view/HOW-TO:Modify_the_video_cache

5

Sorry for the late answer. So I tested the latest firmware (I updated 13.04. and not used the patch what you suggested) I had not experienced dropout with 88.2 Khz 2.0 and 5.1 FLAC, but yes with 192 Khz 2.0. :frowning:

But I experienced an another issue. So if I switched the playback between the two version of a track (2.0 and 5.1) without stopping the playback the output channel depth does not changed so the 5.1 channel version was played in 2.0. But if I stopped the playback and started after the other one the output channel depth was changed (the frequency was same 88.2 khz).

6

That is expected. See “output configuration” http://kodi.wiki/view/Settings/System#Audio_output

7

I am sorry but I checked the “output configuration” settings and do not understand what you are mean about “expected”. I am using the “best match” setting so in my interpretation if I the play list contains titles with various sample rate that is play with various output frequency. Am I wrong?

Regarding the dropouts I can confirm the problem still exist with the 192 KHz 2.0 samples. (I am using the latest OSMC firmware).

8

The current version does not play the 192 KHz 2.0 and 88.2 kHz 5.1 24 bit FLAC samples at all. The iOS (and the WEB) remote app showing the playback time progress but no audio output.

9

Can you post a debug log and output of:
tvservice -a

10

Sorry but I am not an expert in this log sharing yet. So I uploaded the debug log (http://paste.osmc.io/igetacuboy.vhdl) with two track playback test.
Having regard to “tvservice -a” output can you help me how I could be produce it?

11

This is the path to console/putty

12

Thanks ActionA.

Here is the “tvservice -a” output.
PCM supported: Max channels: 8, Max samplerate: 192kHz, Max samplesize 24 bits.
AC3 supported: Max channels: 8, Max samplerate: 48kHz, Max rate 640 kb/s.
DTS supported: Max channels: 8, Max samplerate: 48kHz, Max rate 1536 kb/s.
DTS_HD supported: Max channels: 8, Max samplerate: 192kHz, Max rate 8 kb/s.

At least the DTS_HD Max rate looks like a little bit interesting…

As I know my receiver support the 96Kz/24 bit DTS also.

13

After I upgraded the system today the playback is working with the 192-2.0 and 88.2-5.1 tracks.

Unfortunately the dropout still exist but I experienced just the 192-2.0 tracks only, the 88.2-5.1 tracks played perfectly.

14

What does “vcgencmd version” report? There was a fix for high samplerate audio, but I’m not sure if it’s in the current osmc build.

15

Apr 6 2015 13:30:31
Copyright © 2012 Broadcom
version 52e98d667b8b6ef27a2df8d817807701057bb30d (clean) (release)

16

Could be network bandwidth - can you try playing from local storage (sdcard/usb)?
Or enable buffermode=1 (http://kodi.wiki/view/HOW-TO:Modify_the_video_cache#Cache_settings)

Alternatively limit the sample rate we use over hdmi. Try (in config.txt)
hdmi_samples_limit=192000

17

I tried both from network and SD card but but I had dropouts in both cases. I am not sure but maybe the dropout more frequent if the source is network.

I changed the buffermode to 1 and also increased the cachemembuffersize to 67108864 but unfortunately no success.

18

After I added this settings to the config.txt the HDMI sample out was 96KHZ during the 192KHZ track playback.

19

But did it avoid the drop-outs?

20

Unfortunately I have not enough time to test the playback with this settings, but:

  • I not experienced dropout during the playback of more tracks (source network)
  • but if I start the playback after the RP2 booted from power off state the output sample rate was just 48KHz. If I rebooted the device using the iOS Kodi app the playback output was the expected 96 KHz.

I can test the playback more during the weekend…