How can I find the "Format specific options" info within an mkv file?

[doom-nine]

Hello guys, I am just looking for a way to find the info in an mkv file.

When I packed the video and audio into one mkv file, I set some parameters at the "Format specific options". The parameters set were "Delay (in ms)" and "Stretch by", maybe others. Here comes the problem: I totally forget them.

I tried mkvinfo GUI, as well as the Header Editor... all failed. But I believe the info must hide somewhere within the mkv file. Can anyone tell me how to recovery it? :p

[LoRd_MuldeR]

I'm just speculating here, but doesn't mkvmerge simply add the "Delay (in ms)" as a constant offset to all the timestamps?

If so, it would be impossible to recover the "Delay (in ms)" value without comparing the file's timestamps to the original (unmodified) timestamps.

Same applies to "Stretch by", because it's probably just a factor that mkvmerge multiplies to all timestamp values...

[doom-nine]

I'm just speculating here, but doesn't mkvmerge simply add the "Delay (in ms)" as a constant offset to all the timestamps?

If so, it would be impossible to recover the "Delay (in ms)" value without comparing the file's timestamps to the original (unmodified) timestamps.

Same applies to "Stretch by", because it's probably just a factor that mkvmerge multiplies to all timestamp values...
Thanks for reply. mmm... Sounds like bad news. :(

I don't quite understand the technical thing. If I play the mkv, all is well. So I assume the info may be hidden somewhere, at least players can "see" it. But if I extract the streams out of the mkv file, all "Format specific options" are gone... I am really curious how players "see" it. If players can, I can as well. Yet I don't know how to...

[LoRd_MuldeR]

Thanks for reply. mmm... Sounds like bad news. :(

I don't quite understand the technical thing. If I play the mkv, all is well. So I assume the info may be hidden somewhere, at least players can "see" it. But if I extract the streams out of the mkv file, all "Format specific options" are gone... I am really curious how players "see" it. If players can, I can as well. Yet I don't know how to...

Well, usually each frame or each group of frames (called "block" or "cluster", respectively, in MKV terminology), has a so-called "timestamp" or "timecode" attached, which tells the player when to display that specific frame.

Applying a "delay" to the stream then simply means that a certain constant value (offset) will added to or subtracted from each timestamp in the stream. In other words: Not the delay itself is stored in the file. Instead, the individual timestamps are modified according to the desired delay value. Consequently, the player isn't aware of the "delay" that you applied and it also doesn't have to be. It still displays each frame exactly at the time that the frame's individual timestamp specifies.

And, unless you know what the original timestamp values were, you neither know whether any delay had been applied nor how much it was (if any). So the info probably is not "hidden", it simply is not present...

[gpower2]

Well, gMKVExtractGUI writes the delay of each track in relation to the video track, so perhaps this will help you. ;)

[foxyshadis]

Format specific options are just mkv properties that aren't available for all types of tracks or codecs. Aspect ratios are meaningless for audio, obviously, and AAC is SBR doesn't make sense for FLAC.

Delay is actually not a format-specific option, but it's on that page just because it makes the most sense near the other options. It'll show up on the track info in MediaInfo as usual, like all the rest. Edit: You have to enable advanced mode in MediaInfo to see the Delay.

[doom-nine]

Thanks to my friends above. I sort of understand. I tried gMKVExtractGUI, but cannot find the delay info either... Sems impossible to get the parameters back. :(