problems skipping forward / backward on an mkv file.

[rotchild]

Ok, so I searched all over for this, and most solutions come short and are from years past.

I'm trying to play this 17GB (2 hours and a half movie) .mkv file (on VLC). File loads up fine (and fast) and it plays fine (subtitles and everything)... The problem comes when skipping ahead (or back). I customized a shortcut in which I use the keyboard arrows alone to skip as little as possible (I guess it skips 3 seconds per press). To skip this 3 seconds, sometimes it takes 5 seconds (so skipping is pretty much useless), but like, if I click on the time bar, to say, 30 minutes ahead... I mean, the movie just pauses, and I go make some coffee, and come back. It feels like it takes minutes to skip. It's pretty much like watching a VCR tape again

I switched the "0 to 2" threads in the decoding section of FFMpeg codec option. I guess it improved a little bit, but not that much, I'm afraid.

It's definitely not my hardware. I tried the file on both my mechanical and in my SSD drive. In both the file shows the same behavior.

I don't wanna convert to mp4, as I'll loose the subtitles. And I know close to nothing about demuxing... Please help.


Edit: This doesn't happen with other smaller (like 0.5 GB's) .mkv files on the same hard drive, so...

[butterw]

2 possibilities:

1) Your system can't handle the high bitrate of this file with VLC (+settings). Try with another player such as mpc-hc portable (default config).
You also want to activate any fast-seek to keyframes options.


OR

2) there is an issue with the file.
a) try remuxing the mkv with mkvtoolnix or ffmpeg
b) try demuxing to mp4+external subs

[rotchild]

2 possibilities:

1) Your system can't handle the high bitrate of this file with VLC (+settings). Try with another player such as mpc-hc portable (default config).
You also want to activate any fast-seek to keyframes options.

Thanks for the reply!
MPC-hc performes just a little bit better (in regard to the issue), but somehow the colors get messed up for whatever the reason...

OR

2) there is an issue with the file.
a) try remuxing the mkv with mkvtoolnix or ffmpeg
b) try demuxing to mp4+external subs

2) I figured as much :\
a) didn't work, output file = same size and same issues
b) I was able to extract one hevc (or h265) file, 2 audio files (supposedly one stereo and one 5.1, although they are the exact same size, and the .srt subtitle file). The video file plays fine on VLC, but when I open the .srt file, no subtitles are displayed, at all, and obviously there's no audio tracks (can't seem to add them from the extracted audio files)

I wish this wasn't so complicated
Thanks again...

[butterw]

You could post the mediainfo text output for your original mkv file. (x265 10bit HDR, with high resolution/bitrate for instance is going to be quite a bit more challenging than regular x264 to play back smoothly on an older system). Colors looking washed out in mpc-hc would suggest its HDR content. HDR-to-SDR tonemapping can be ressource hungry.
You should look at %ressource usage cpu/gpu (in Windows Task Manager, CTRL-Shift-Esc).

You can remux the elements in mp4 with ffmpeg, maybe stick with a single audio. https://forum.videohelp.com/threads/398507-Top10-Commands-for-Lossless-Video-manipulat...eg-%28Guide%29

srt subtitles are in text format, typically they should have the same name as the file if you want them autoloading (and in any case you should be able to load them manually).

[rotchild]

media info below:

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5@High
HDR format : SMPTE ST 2086, HDR10 compatible
Codec ID : V_MPEGH/ISO/HEVC
Duration : 2 h 29 min
Bit rate : 15.0 Mb/s
Width : 3 840 pixels
Height : 1 634 pixels
Display aspect ratio : 2.35:1
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.080
Stream size : 15.6 GiB (96%)
Language : English
Default : Yes
Forced : No
Color range : Full
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Mastering display color primaries : Display P3
Mastering display luminance : min: 0.0050 cd/m2, max: 1000 cd/m2
Maximum Content Light Level : 1000 cd/m2
Maximum Frame-Average Light Level : 200 cd/m2


It's not such an old system. It's an i5, Windows 10, 970 GPU, 16 GB Ram, SSD... I mean, as I said other mkv files do fine.

Yes, I manually selected the .srt file with VLC. It displays nothing... here's the info on it too (not sure if it has anything to do with it):

Text
ID : 4
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Duration : 2 h 24 min
Bit rate : 63 b/s
Count of elements : 1720
Stream size : 66.8 KiB (0%)
Title : English Captions
Language : English
Default : Yes
Forced : No

[butterw]

from a quick search: it seems gtx 970 doesn't have full hw support of hevc (only hybrid).
Mpc-be would be a good alternative player as it has built-in tonemapping out of the box like VLC and might perform slightly better.

Your srt subtitle file shows up as a subtitle track in the interface but doesn't display at all when enabled ?
The content of the file might be empty or have a syntax error at the start. Check the content of the demuxed .srt, ex:

1
00:00:09,442 --> 00:00:10,176
Hello there.

2
00:00:13,246 --> 00:00:13,847
Hi.

[rotchild]

Thanks mate. MPC-be worked fine... Aside from a few "intervals" of the file, that seem to be inaccessible from skipping (the movie just freezes), but if you play through it, they're fine.

I finished watching and will just delete the file... Too much trouble. Not my first bad experience with .mkv files

Your srt subtitle file shows up as a subtitle track in the interface but doesn't display at all when enabled ?
The content of the file might be empty or have a syntax error at the start. Check the content of the demuxed .srt, ex:

Yep, the .srt file has all the content. The only reason I believe it wouldn't work it's because it's attached to a .hevc file (or .h265).

Anyways, all gone now.

[butterw]

High bitrate spikes in the encode will cause issues.
Trouble with seeking (which stresses the system more) suggests your system had unsufficient headroom to deal with it.

If your cpu has an integrated gpu with hw accelerated decoding of 4K Hevc 10bit, it likely would perform better than GTX970 in this task.