4.6.4.0 - Certain videos freezing on certain clients

[rexerm 36]

Last night, one of my users was experiencing a lot of stuttering and eventual freezing of playback.  I was able to sort of replicate this myself, and discovered that the movie would play differently on different clients:

Chrome - would freeze consistently at a certain timecode

Edge - would glitch badly at this same timecode, then proceed

Samsung TV App & Emby Theater for Windows - played perfectly

Even stopping playback, verifying the transcoding temp directory was empty, and restarted resulted in the same issue.

I'd seen this sort of thing with a different movie in the past and  tested that again this morning. Similarly, that one would freeze playback on Chrome and Android, but play fine in Theater. Strangely, this file would freeze at slightly different timecodes within a 2 minute range and was not consistent.

This feels like some sort of issue with transcoding...  I tested with hardware acceleration turned on and off, but that did not make a difference. Is this related to the bug fixed in my other thread, perhaps?  I have not installed the beta, so am still on 4.6.4.0 and have not tried the fixed version.

Edit to add; I don't have a proper GPU, just an Intel UHD 630 at the moment. 

 

Edited September 27, 2021 by rexerm

[Carlo 4561]

Hi, typically when you only see this happen with only a couple pieces of media it's not system related but the media itself.
Sometimes it's just bad headers in the file and remux can fix it.  Other times you may need to just replace the media itself.

As an experiment, try playing one of these back in Theater but this time force it to transcode.  You should be able to do this in the OSD click the cog icon and lowering the Quality.
Does it still play when transcoding in Theater or does it have the same issue?

[Luke 42078]

Also can we please look at an example?

Thanks !

[rexerm 36]

Thank you! I've PMed a link to the two files I've been testing amd the logs:

test1.mkv
From a DVD. Between approx 1:31:50 and 1:35:30, transcoded playback will often freeze completely. Occasionally, it will get past this point, but inevitably playback will simply stop before the end of the file is reached and the episode is marked "played" by Emby.  I directly remuxed with a newer version of MKVToolnix, but no change. I demuxed the video and audio into separate files and remuxed it again. This seemed to help somewhat, but playback will still pause in spots before continuing. This version of the file is able to play all the way to the end, however.  I've also had reports from users about other episodes from other older shows stopping playback before the end, so it's not isolated to this particular show's release.

In the logs: at 13:22 started playback, skipped to 01:31:45 in the episode. At 13:26, playback prematurely ended (no freezes this time).

test2.m2ts
From a BD, back when I didn't know any better and just used the M2TS container.  Transcoded playback often freezes completely around 00:53:33.  I tried remuxing into an MKV container. This helped somewhat, but the video will often pause in a few spots around this timecode before continuing (audio sounds fine).

In the logs: at 13:27 started playback, skipped to 00:53:24 in the movie, played OK, rewound back to 00:53:19, long video pause at 00:53:23, but recovered and continued playback (strangely, also no permanent freeze this time, either).

Not sure why direct play doesn't experience the same sort of issues, if the fault is in a bad encode or broken container timecode or something else in the original file.  Would changing the h624 encoder setting from "auto" to something slow allow ffmpeg to create more error-resiliant files?

[rexerm 36]

3 hours ago, cayars said:

As an experiment, try playing one of these back in Theater but this time force it to transcode.  You should be able to do this in the OSD click the cog icon and lowering the Quality.
Does it still play when transcoding in Theater or does it have the same issue?

Theater did have the same issues when I forced the transcode, yes.

[Carlo 4561]

Thanks for trying that.  That to me would indicate it's the media itself.
Do you know how to remux a file outside of Emby?

[rexerm 36]

3 minutes ago, cayars said:

Thanks for trying that.  That to me would indicate it's the media itself.
Do you know how to remux a file outside of Emby?

Yes, I wrote about that my second post above - there were varying degrees of success from that, but nothing perfect.  However, there's nothing particularly strange about these files, having come directly from my own discs.  Would there be a technical reason direct playing these files is fine, but transcoding them introduces issues clients seem to not handle well?

[rexerm 36]

7 hours ago, Luke said:

Also can we please look at an example?

I'm also uploading another example file and logs that one of my users let me know about. A different episode from a different show, ripped by me using MakeMKV from my own disc.  Freezes for me at 18:58 (or sometimes a little before that).  He reported it ending early around this time and marking the episode "watched," rather than freezing.

Seems bizarre that plain old standard DVD rips would stuggle so much.

[Carlo 4561]

Would you be able to provide one of these problem files for testing?

A link to Dropbox or Google Drive would be good.

[rexerm 36]

2 minutes ago, cayars said:

Would you be able to provide one of these problem files for testing?

A link to Dropbox or Google Drive would be good.

Yep, I've PMed to Luke some files and logs.  I'll send you the same. Thank you!

[Luke 42078]

Is the issue only when transcoding? If so then please attach the ffmpeg log. thanks.

[rexerm 36]

23 minutes ago, Luke said:

Is the issue only when transcoding? If so then please attach the ffmpeg log. thanks.

The transcoding logs are in the same shared folder as the test videos.  The link to this is in the PM I sent yesterday titled "test files and logs."  Easier than trying to remember to edit out my IP/DNS stuff from everything.

[Luke 42078]

@rexerm are you still running into this?

[rexerm 36]

Hi @Luke - yes, still having issues when these certain files get transcoded.

[Luke 42078]

On 9/27/2021 at 3:42 PM, rexerm said:

Would there be a technical reason direct playing these files is fine, but transcoding them introduces issues clients seem to not handle well?

Depending on that factor, the file will be decoded in different places and if there is a problem with the file it will depend on how will those places handle it.

[Luke 42078]

Can you provide a sample video for testing?

[rexerm 36]

9 hours ago, Luke said:

Can you provide a sample video for testing?

I'll resend the PM with a link to a mega folder that contains both the transcoding logs and sample videos.

[rexerm 36]

Updated to 4.6.5.0 today, hoping the new ffmpeg it contained might help.  But tested the Night Gallery episode (test1.mkv) and it still quit playback early...

[Luke 42078]

Hi, sorry, it doesn't have a new ffmpeg. That's in the 4.7 beta channel as it needs more time in testing.

[Luke 42078]

I haven't downloaded all of the samples, but are they all with either vc1 or mpeg2 video?

[rexerm 36]

MPEG2 for the two smaller files (episodes), H.264 for the movie.  I just re-ripped the movie from a different copy of the Blu-ray, but I am still having issues with it at the same timecode as the older rip I uploaded.

[Luke 42078]

Good news @rexerm, I was able to reproduce with test1.mkv in the exact spot you mentioned. We are working on resolving that for the 4.7 release. Thanks.