Movie transcoding but if I remux from MP4 to MKV it direct plays?

[Lane03 14]

I'm trying to get away from Plex but have noticed a number of my movies that would direct play in Plex are triggering a transcode in Emby (as well as BlueNeon based on the old Emby). After much testing I found that if I remux the streams into a MKV container then the movie will direct play without issue. Seems to be a bug with the auto-detection process of what can direct play and what can't, as the original MP4 plays just fine on Plex or using the Roku Media Player via USB drive.

 

Roku is wired and has bitrate set at maximum. I can't see how it's a setting or config issue since remuxing it from MP4 to MKV fixes it.

 

What info would you need from me to look into this?

[Lane03 14]

Need to do some more testing, but it appears to be fixed. I was running an outdated version of Emby Server. Updated to the latest version and the two movies I've checked so far are direct playing where before it was triggering a transcode unless I remuxed them to MKV.

[Luke 42077]

Thanks for the feedback !

[Lane03 14]

Thanks for the feedback !

No problem. This was a good example though of why we really need a way to tell from within the Emby Roku app if the movie is direct playing or transcoding, as it really helps with troubleshooting. I realize you might be trying to avoid cluttering up the UI, but perhaps something simple like having the retrieving bar be a different color or a small icon when you bring up the on screen display.

[mark19721964 13]

I literally just had this happen. I recorded a lifetime movie, encoded to h.265 AAC 2.0 in MP4 format... and I noticed when I played it on Emby it looked terrible... it was transcoding...I remuxed it to MKV and it direct played. the dashboard said something about transcoding HLS... I don't get it. It's just a different container... same codecs.... I'm so glad most of my stuff is MKV format.

Edited May 26, 2025 by mark19721964

[ebr 16169]

18 hours ago, mark19721964 said:

I literally just had this happen. I recorded a lifetime movie, encoded to h.265 AAC 2.0 in MP4 format... and I noticed when I played it on Emby it looked terrible... it was transcoding...I remuxed it to MKV and it direct played. the dashboard said something about transcoding HLS... I don't get it. It's just a different container... same codecs.... I'm so glad most of my stuff is MKV format.

Hi.  This is an incredibly old thread but different containers have different capabilities.

[mark19721964 13]

I did not want to start a new thread so I google searched. It brought me to this. I was under the impression that it was less to do with the container (especially common ones like mkv or mp4) and more about what codecs were used. Where can I find more info on this without getting lost in searches?

[Luke 42077]

Just now, mark19721964 said:

I did not want to start a new thread so I google searched. It brought me to this. I was under the impression that it was less to do with the container (especially common ones like mkv or mp4) and more about what codecs were used. Where can I find more info on this without getting lost in searches?

HI, did you explore the stats feature in the video player to learn why it was transcoding?

[mark19721964 13]

No. I wish I had... I quickly saw it was transcoding and then remuxed it, added it back to drive and it direct played... Next time that happens I definitely will. I do know it was x265 which roku supports... so I went to other files that are in MP4 format with x265 to check them and they direct played fine... 

[speechles 2055]

If there is some kind of error

16 minutes ago, mark19721964 said:

I did not want to start a new thread so I google searched. It brought me to this. I was under the impression that it was less to do with the container (especially common ones like mkv or mp4) and more about what codecs were used. Where can I find more info on this without getting lost in searches?

You log directory should have the output produced by ffmpeg. It should give the exact reason why. You can add the ffmpeg log here as an attachment. We can then help you understand what was happening. Next time it happens check your logs directly for something from ffmpeg.

You can also bring up the OSD of the video player as mentioned above. Then use the cog/gear button and choose "Stats for Nerds" and it will turn them on. The reason for transcoding and some other info will be shown on screen.

[mark19721964 13]

1 hour ago, speechles said:

If there is some kind of error

You log directory should have the output produced by ffmpeg. It should give the exact reason why. You can add the ffmpeg log here as an attachment. We can then help you understand what was happening. Next time it happens check your logs directly for something from ffmpeg.

You can also bring up the OSD of the video player as mentioned above. Then use the cog/gear button and choose "Stats for Nerds" and it will turn them on. The reason for transcoding and some other info will be shown on screen.

 

ffmpeg-transcode-40dc5b14-d0bd-4c65-a587-a48c24a19688_1.txt

[speechles 2055]

TranscodeReasons=VideoFramerateNotSupported

"AverageFrameRate":23.995483,"RealFrameRate":150

This happens when the MP4 container has a variable framerate. It likely can play this item directly on the Roku but it throws off the auto-detection when the framerate expands. The server believes the framerate is too high since the Roku reports a maximum of 60. When you convert it to MKV it fixes the issue by setting the header correctly for the framerate.

 

Edited May 28, 2025 by speechles