MKV container - Get frame count without extracting (CFR source)?

[Interpolator]

I don't know whether or not the frame count is contained in the container itself.

With eac3to, I could extrapolate it from the time, but that's only an approximation since the time is just reported to the nearest second, only and horribly time consuming.

These are for approximately 300 .MKV files, thankfully all with constant frame-rate sources (don't get me started variable frame rate lunacy).

Nearest workaround I can think of is to script extracting the video and then delete it, but it occurred to me there may be some others here who have had a similar need and scripted it.

AviDemux has wisely gone to time-based vs. frame-based to deal with VFR, but foolishly completely abandoned ability to display frame count and go to specific frames.

MeGUI's HD extractor is a front end for eac3to, but doesn't batch, and the frame count is only displayed in the log file created.

Suggestions?

[poisondeathray]

If accuracy isn't paramount, perhaps mediainfo or ffprobe in commandline mode to batch it . For CFR sources, they should be accurate enough

To be accurate, you have to index the file which is much slower (basically count the frames by scanning instead of using a calculation based on frame rate and duration). This can be done without demuxing - for example FFMS2 in avisynth - but its more difficult to batch

[Dougster]

Selur's Hybrid displays a frame count upon opening a file. Not sure how it calculates it though. I have found it useful to determine
if the frame count for a PAL DVD matches the frame count for a 25i Blu-Ray just so I could extract the DVD audio (AC-3) to use for
a re-encode of the Blu-Ray.

[Interpolator]

Thanks, both of you, for your responses.

I poked a bit and it turns out eac3to creates the log file that displays the frame count even if the video file is not extracted. I imagine it tallies each frame and simply doesn't extract the data but rather skips over it. I needed to fetch the SRT anyways, so the following does the job:

for /R %A in (*.mkv) do (eac3to "%A" 3:"%~nA.srt")

Nothing a little Interpolation can't do, right?

[El Heggunte]

I poked a bit and it turns out eac3to creates the log file that displays the frame count even if the video file is not extracted.

I imagine it tallies each frame and simply doesn't extract the data but rather skips over it.

Equally possible (and more probable, I.M.O.): eac3to reads and counts the video timestamps.