Does Rasplex support PCM/LPCM passthrough?

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1

Hi folks,

just realized that I posted my question in the wrong forum (didn't see this subforum for Rasplex) so here goes and sorry for double post. Short question, does Rasplex support PCM passthrough?

Long question:

Main issue: I've been ripping my Blu-Ray collection like crazy and watch them over Direct Play with Rasplex. Everything is working fine except those few movies that uses LPCM as codec (both Stereo and 5.1). I've been searching for a solution but cannot find any indiciation that PCM shouldn't work. The RPi is hooked up with my receiver via HDMI. DTS and AC3 passthrough is working like a charm. Is the RPi uncapable of passing through LPCM?

Second issue: Transcoding to AAC is an ok solution. One weird thing through: when I playback a video with LPCM on Rasplex both video and audio are transcoded which my server cannot cope with. Why isn't only the audio transcoded?

I've been searching high and low for a solution but I cannot find anything. Not to my main issue nor to my second issue. Is there someone that has a couple of hints?

2

Hi folks,
just realized that I posted my question in the wrong forum (didn't see this subforum for Rasplex) so here goes and sorry for double post. Short question, does Rasplex support PCM passthrough?
Long question:
Main issue: I've been ripping my Blu-Ray collection like crazy and watch them over Direct Play with Rasplex. Everything is working fine except those few movies that uses LPCM as codec (both Stereo and 5.1). I've been searching for a solution but cannot find any indiciation that PCM shouldn't work. The RPi is hooked up with my receiver via HDMI. DTS and AC3 passthrough is working like a charm. Is the RPi uncapable of passing through LPCM?Second issue: Transcoding to AAC is an ok solution. One weird thing through: when I playback a video with LPCM on Rasplex both video and audio are transcoded which my server cannot cope with. Why isn't only the audio transcoded?
I've been searching high and low for a solution but I cannot find anything. Not to my main issue nor to my second issue. Is there someone that has a couple of hints?


This is available in the latest release, have you updated to 0.6.0?
3

I updated today since I had a problem with BluRay-rips and AC3 making the movie lag. This is now working (yay). I get the message "unknown codec: PCM" when playing back and both audio and video are transcoded. Do I have to check something in the settings?

FYI:

RasPlex:~ # tvservice -a
     PCM supported: Max channels: 8, Max samplerate: 192kHz, Max samplesize 24 b               its.
     AC3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   MPEG1 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     MP3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   MPEG2 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     AAC supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DTS supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   ATRAC supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DSD supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
    EAC3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
  DTS_HD supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     MLP supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DST supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
  WMAPRO supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
Extended supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
4

I updated today since I had a problem with BluRay-rips and AC3 making the movie lag. This is now working (yay). I get the message "unknown codec: PCM" when playing back and both audio and video are transcoded. Do I have to check something in the settings?

FYI:

RasPlex:~ # tvservice -a
     PCM supported: Max channels: 8, Max samplerate: 192kHz, Max samplesize 24 b               its.
     AC3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   MPEG1 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     MP3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   MPEG2 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     AAC supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DTS supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
   ATRAC supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DSD supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
    EAC3 supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
  DTS_HD supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     MLP supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
     DST supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
  WMAPRO supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.
Extended supported: Max channels: 8, Max samplerate: 192kHz, Max rate 2040 kb/s.

I too have this issue; i get the 'Unknown codec' in rasplex prompting a video and audio transcode down to ACC. Here is the PCM info. 

Audio
  • Codec PCM
  • Channels Stereo
  • Bitrate 1536 kbps
  • Language English
  • Bit Depth 16
  • Bitrate Mode CBR
  • Duration 1:43:40
  • Profile pcm_s16le
  • Sampling Rate 48000 Hz
  • Title Stereo
5

I too have this issue; i get the 'Unknown codec' in rasplex prompting a video and audio transcode down to ACC. Here is the PCM info.


Audio

  • Codec PCM
  • Channels Stereo
  • Bitrate 1536 kbps
  • Language English
  • Bit Depth 16
  • Bitrate Mode CBR
  • Duration 1:43:40
  • Profile pcm_s16le
  • Sampling Rate 48000 Hz
  • Title Stereo
Might be worth remuxing your file to AAC stereo, only takes a couple of minutes.
6

Yep, I added an acc and ac3 track to the mkv along with the pcm. It plays direct in rasplex now as I have the mpeg2 licence. Rasplex should pass pcm though. It was the file here (20 sec sample): https://www.dropbox.com/s/b6rbbb7xm2jamzb/My%20Winter%20Journey%2020s.mkv?dl=0


Without the acc and ac3 in the mkv it transcodes when it should really pass the pcm and play the mpeg2 direct.

7

Of course it is possible to remux the audio but I'm ripping my whole movie collection and it would be nice not to touch the files at all. Since it should be supported and such a normal codec I would like to know if it is possible to solve this problem. I've updated to 0.6.0, it's a Raspberry Pi B+. The Rpi2 just arrived in the mail and I will try that out too shortly.

8

Of course it is possible to remux the audio but I'm ripping my whole movie collection and it would be nice not to touch the files at all. Since it should be supported and such a normal codec I would like to know if it is possible to solve this problem. I've updated to 0.6.0, it's a Raspberry Pi B+. The Rpi2 just arrived in the mail and I will try that out too shortly.


When I am at my computer I'll post a bug report on https://github.com/RasPlex/RasPlex/issues

That's the place for these things, I believe.
9

I thought there might be some setting that I cannot find for this. Anyway, the RPi2 doesn't work with PCM either.

10

Yep, I added an acc and ac3 track to the mkv along with the pcm. It plays direct in rasplex now as I have the mpeg2 licence. Rasplex should pass pcm though. It was the file here (20 sec sample): https://www.dropbox.com/s/b6rbbb7xm2jamzb/My%20Winter%20Journey%2020s.mkv?dl=0

Without the acc and ac3 in the mkv it transcodes when it should really pass the pcm and play the mpeg2 direct.

Rasplex will only play MPEG2 direct if you have the licence from raspberrypi.org and have applied the licence number to the config.txt file, otherwise it will transcode, same with VC-1(.wvm).

11

Rasplex will only play MPEG2 direct if you have the licence from raspberrypi.org and have applied the licence number to the config.txt file, otherwise it will transcode, same with VC-1(.wvm).

I have the license and it is initialised; rasplex can play mpeg2 and VC1 direct. It is PCM that it will not passthrough. See my post here: https://github.com/RasPlex/RasPlex/issues/372

Rasplex does the same for 264 files inside mkv: unknown codec: PCM

12

I thought there might be some setting that I cannot find for this. Anyway, the RPi2 doesn't work with PCM either.

When I am at my computer I'll post a bug report on https://github.com/RasPlex/RasPlex/issues

That's the place for these things, I believe.

Can either one of you create a short sample of an affected file so we can have a look at it, we don't need the whole file.  Thanks

13

I thought there might be some setting that I cannot find for this. Anyway, the RPi2 doesn't work with PCM either.

When I am at my computer I'll post a bug report on https://github.com/RasPlex/RasPlex/issues

That's the place for these things, I believe.

Sorry, just noticed samples on Github, thanks.

14

I thought there might be some setting that I cannot find for this. Anyway, the RPi2 doesn't work with PCM either.

When I am at my computer I'll post a bug report on https://github.com/RasPlex/RasPlex/issues

That's the place for these things, I believe.

Have you tried connecting your RPi directly to your TV by HDMI (bypassing the receiver), and playing one of the files, to rule out problems with your receiver?

15

Have you tried connecting your RPi directly to your TV by HDMI (bypassing the receiver), and playing one of the files, to rule out problems with your receiver?

What I have done is select 20mbps transcode in rasplex (instead of Direct play) of an episode of Hannibal that has DTS; when I do this PCM audio is passed successfully. Please see log: https://dl.dropboxusercontent.com/u/13997835/hannibal/Plex%20Media%20Server.log

So it seems that rasplex cannot pass PCM using direct play? What did you find from the samples on Github? My receiver is a Yamaha RX-V377 and the manual says:

pcm.jpg

16

What I have done is select 20mbps transcode in rasplex (instead of Direct play) of an episode of Hannibal that has DTS; when I do this PCM audio is passed successfully. Please see log: https://dl.dropboxusercontent.com/u/13997835/hannibal/Plex%20Media%20Server.log
 
So it seems that rasplex cannot pass PCM using direct play? What did you find from the samples on Github? My receiver is a Yamaha RX-V377 and the manual says:
 
pcm.jpg


Linear PCM (LPCM) is different to PCM.
17

What I have done is select 20mbps transcode in rasplex (instead of Direct play) of an episode of Hannibal that has DTS; when I do this PCM audio is passed successfully. Please see log: https://dl.dropboxusercontent.com/u/13997835/hannibal/Plex%20Media%20Server.log

So it seems that rasplex cannot pass PCM using direct play? What did you find from the samples on Github? My receiver is a Yamaha RX-V377 and the manual says:

pcm.jpg

It gets more perplexing; I am able to direct play and pass-through PCM on this file: https://dl.dropboxusercontent.com/u/13997835/hannibal/2195.xml

See log: https://dl.dropboxusercontent.com/u/13997835/hannibal/other.log

So there is something that rasplex does not like about certain PCM audio?

18

Linear PCM (LPCM) is different to PCM.

The file I attached to GitHub (https://dl.dropboxusercontent.com/u/13997835/winter/one.mkv) was LPCM:

Untitled.jpg

And anyhow:

Receiver is capable:
PCM supported: Max channels: 8, Max samplerate: 192kHz, Max samplesize 24 bits. 
AC3 supported: Max channels: 6, Max samplerate: 48kHz, Max rate 640 kb/s.
DTS supported: Max channels: 7, Max samplerate: 96kHz, Max rate 1536 kb/s.

19

To be clear. The codec is in my case in fact LPCM, the message is however saying "unknown codec: PCM". Is this a bug or is it just not implemented?

20

To be clear. The codec is in my case in fact LPCM, the message is however saying "unknown codec: PCM". Is this a bug or is it just not implemented?

Confirmed my receiver can do PCM, LPCM, and, in fact, rasplex can pass PCM from certain files (see post) just not from the ones I uploaded to GitHub. Use mkvtoolnix (https://www.bunkus.org/videotools/mkvtoolnix/downloads.html) to create some samples of files with problems and add those to the GitHub post i opened. The more info they have the better they can identify the problem. I just split out 20 second samples.

I posted a file to Github that can pass PCM and Direct play: https://dl.dropboxusercontent.com/u/13997835/winter/three.mkv