Seek time issues with Unprocessed MKV

I have two movies recorded from the same Comcast Channel (SyFyHD, with an AVC stream). They have been both run thru MCE Buddy to remove the commercials. With one (Oder of the Phoenix), I converted the container to mp4 (which also re-encoded the video, i.e. the MP4 normal profile). The other (Half Blood Prince), I just converted to the mkv container with no video conversion. I generally prefer the latter, as it does no re-encoding of the video.

I am using Plex Media Server (PMS) a Win7 machine and watching the videos from the web interface on the same computer (i.e. I am using the same computer for the PMS as well as the viewer). The latter takes considerably longer to seek than the former after stopping the video and restarting (around the 2 hr mark).

Specifically, for Half Blood Prince (mkv) takes about 30 seconds to start playing when I restart at the 2 hr mark.

The Order of the Phoenix takes about 5 seconds to do the same.

I will attach the media info files for both to show the detailed info about the files. They both have AVC video High@L3.2, but the details differ, e.g. one has a variable bit rate mode, the other has a constant bit rate mode.

Note that I have also seen this huge difference in seek times on my Nvidia Shield TV Plex client.

I am also uploading to the ftp site the full video file of the slow seeking Half-Blood Prince under my user name.

Can anyone clarify why seek times for the two files would be so different?

Half-Blood Prince.txt (4.8 KB)
Order of the Phoenix.txt (5.0 KB)

As an update, I have found the issue, and it seems to be the MKV Unprocessed mkv file writer. From another forum, I was told that the MCE writer has a record of creating mkvs that often do not play well in a lot of environments. The remedy was to take the mkv file produced by MCEB, then run it through mkvtoolnix, with no intentional changes in the stream content…

The resulting output mkv file from mkvtoolnix plays very well on all of my clients, and there is hardly any seek time delay. While the streams and tags appear to be the same, the mkv writing library used is different.

So if you have seek time issues, even if your file is not a MKV Unprocessed file (even a different container file format), consider using mkvtoolnix and let us know your results.

I have uploaded both the pre-mkvtoolnix and post-mkvtoolnix version of my file to the ftp server under my user name, klaberte

Devs, a few questions:
-Is there any way to use the same library for writing mkv files as is used by mkvtoolnix (perhaps making it an option in the profile)?
-If not, is there any way to automatically trigger sending the file generated by MCEB to mkvtoolnix for post-processing?

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MCEBuddy does use MKVTools to create MKV files but it depends on how your profiles is setup. You can tell MCEBuddy to use ffmpeg to create MKV file or use MKVToolNix. If you attach your conversion log we can check and tell you how your profile is setup and what changes to make if any

Harry Potter and the Order of the Phoenix 20070712 [20180810-0129].mpg-MKV Unprocessed KL-2018-08-11T14-43-51.7398676-04-00.log (1.9 MB)

Here’s the log file. Thanks in advance.

You’re using the MKV Unprocessed profile which has ffmpeg directly create a MKV file

ffmpeg-general=-threads 0
ffmpeg-video=-ss 0 -vcodec copy -map 0:v -sn
ffmpeg-audio=-acodec copy -map 0:a
ffmpeg-audioac3=-acodec copy -map 0:a





This will make MCEBuddy use MKVToolNix to convert the TS file generated by ffmpeg to MKV.

The reason MCEBuddy uses ffmpeg to create MKV files directly in this Unprocessed profile is that some of the files created by MKVTools don’t play with some software and some Samsung TV’s. See this post for details:

Feel free to share this feedback/link with the other forums where you found the above advice as well.

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This works! Thank you for your help.