DTS and interlaced video clash

[staticmotion 4]

Hi all. I've discovered a weird bug in playback and transcoding... With the "no video transcoding" option ticked in the server:

 

non-interlaced H264 video + DTSMA = plays as expected, i.e. video is direct play, audio is transcoded to AC3

interlaced H264 video + DTSMA = fail

(the same) interlaced H264 video + PCM = plays as expected, i.e. video and audio direct play

 

These are the results if playing through the Emby app. Putting the three files on a USB stick and putting in the one connect box = all three files play the video, although obviously I get an audio not supported warning on the first two

 

Interestingly, whilst trying to play the second file on my Samsung and just getting the waiting circle (before the no compatible streams found error), looking at the server dashboard on my phone the server app indicates the video is playing and direct streaming.

 

So, it seems like... the interlaced video is flagged as being fine to give to the Samsung if the audio doesn't have to be transcoded. If the audio is flagged as needing to be transcoded, then and only then interlaced video is also flagged as needing transcoding (which it clearly doesn't as file 3 plays). If I untick the "no video transcoding" then it plays the second file fine, but it's being transcoded... from H264 to H264!

 

Details:

Samsung TV QE55Q90EATXXU, firmware 1335

Emby server 4.3.1.0 and then I tried updating to the latest beta 4.4.0.9

Have attached the media info reported for files 1 and 2 (the audio is identical, used mkvmerge to create short test files - can send these over if needed)

 

Happy to provide any more information as needed!

thanks

 

[SamES 1057]

Hi, looks like you may have missed the attachments.

 

For your second sample (interlaced H264 video + DTSMA), can you please send any remux logs from the server.

 

Feel free to PM a link to the samples, thanks.

[staticmotion 4]

@@SamES Thanks for the reply. Here's the log, and the missing media info. Will PM you a link for the video samples!

media info.zip

embyserver.txt

[SamES 1057]

So with your second sample file, I can see in the server log that the server tries to remux the audio, but an ffmpeg remux log is never created and it fails playback, so the app requests a full transcode.  I can see the transcode ffmpeg log being created.

 

@@Luke, for the failed remux case, I can see see the m3u8 header being dumped in the server log, but I never see ProcessRun launch ffmpeg.  It's like it doesn't even execute the remux step which is probably why it fails to play.  I probably need to get some clean logs for softworkz to check

[staticmotion 4]

Hi, is there any update on this? Do you need anything more from me?

 

thanks

[Luke 42077]

Ffmpeg log?

[staticmotion 4]

Sorry to ask, but is that different from the server log I already posted?

[Luke 42077]

Yes it is.

[Luke 42077]

But to be honest, I don't think there's much we can do for you. You disabled user access to video transcoding, therefore you're asking for problems. Did you make sure to read the help text underneath the option?

[staticmotion 4]

Yes I read the text, thank you, and I understand what that implies. However, you seem to be missing the point I am making. The video shouldn't need to be transcoded. There is an error somewhere in Emby that is suggesting it does need to be, which is incorrect.

[SamES 1057]

@@Luke, staticmotions observation here, which I have confirmed is that:

• a file with interlaced video and AC3 audio will DirectPlay
• a file with progressive video and DTS will DirectStream
• a file with interlaced video and DTS Transcodes
  • The logical expectation is that this last case should DirectStream not transcode as the interlaced video stream can be played directly, only the DTS needs to be converted.  This doesn't appear to be the case.

The logic makes senses, but I'm fairly sure interlaced video is not supported in m3u8 segments

 

When I tested this a while back I could see DirectStream attempts in the server log, but no remux log was created.  If it's not supported then we probably shouldn't be attempting it.    Now that there has been a few server updates I need to test this again for a log file and try an understand what's happening.  I seem to recall the that ffmpeg process was aborting but had no log to confirm it.

 

I can't remember all the details from my testing, but you may already be able to confirm why interlaced files won't DirectStream 

[Luke 42077]

Exactly, you can't put interlaced video in hls, so that's why the video ends up getting transcoded.

[staticmotion 4]

Ah okay, I understand. The streaming protocol won't accept interlaced video. Ugh, how annoying.

 

Is there then a way of changing how the video is being deinterlaced? At the moment it's converting my 25i to 25p, rather than 50p. It completely changes the feel of the video, and makes it look awful.

 

thanks

[Luke 42077]

Options are always possible for the future. Thanks.