Mismatched video fps

[dennbenn]

Mods, I wasn't sure how to title this thread so feel free to rephrase it.

Hey all, I'm stuck on demuxing a few files while backing-up one of my blu-ray discs. I've been demuxing and remuxing my discs for a while and am fairly familiar with how to use video tools (BDInfo, TSmuxer, MKVToolNix, MeGUI, etc) but this one particular disc has been causing some trouble. OK, here goes...

M2TS container info reports that the video stream should be 29.970fps but it's demuxed at 23.976. I've never seen anything like this nor how to correct the stream's meta data back to 29.970 w/o re-encoding. I've tried demuxing with TSmuxer but it throws errors and won't complete the job. MeGUI's HdBrStreamExtractor also demuxes at 23.976 instead of 29.970. Below is eac3to command line and GUI image is attached.

eac3to v3.24
command line: "C:\Users\redacted\Documents\Video Tools\eac3to\eac3to.exe" "G:\redacted\BDMV\PLAYLIST\00004.mpls" -demux
------------------------------------------------------------------------------
M2TS, 1 video track, 2 audio tracks, 1 subtitle track, 0:03:39, 30p /1.001
1: VC-1, 480p24 /1.001 (3:2) with pulldown flags
2: AC3, English, 2.0 channels, 256kbps, 48kHz
3: AC3, English, 2.0 channels, 256kbps, 48kHz
4: Subtitle (PGS), English
[a02] Extracting audio track number 2...
[a03] Extracting audio track number 3...
[s04] Extracting subtitle track number 4...
[v01] Extracting video track number 1...
[v01] Writing new framerate "24fps /1.001" to bitstream.
[v01] Removing VC-1 pulldown...
[v01] Creating file "00006 - 1 - VC-1, 480p24.vc1"...
[a02] Creating file "00006 - 2 - AC3, English, 2.0 channels, 256kbps, 48kHz.ac3"...
[a03] Creating file "00006 - 3 - AC3, English, 2.0 channels, 256kbps, 48kHz.ac3"...
[s04] Creating file "00006 - 4 - Subtitle (PGS), English.sup"...
Video track 1 contains 6566 frames.
Subtitle track 4 contains 31 captions.
eac3to processing took 3 seconds.
Done.


[Attachment 94159 - Click to enlarge]

[Columbo]

You removed the VC1 pulldown so it reverted to 23.976 as it should. Use -keepPulldown if you want to keep 29.97.

Your eac3to is ancient. You should upgrade to the latest 4.02. It will give you a new help file that lists all options, including -keepPulldown.

[dennbenn]

You removed the VC1 pulldown so it reverted to 23.976 as it should. Use -keepPulldown if you want to keep 29.97.

Your eac3to is ancient. You should upgrade to the latest 4.02. It will give you a new help file that lists all options, including -keepPulldown.

Wow, how embarrassing... I can't believe I didn't think of that - thanks for the pointer. Just tried TSmuxer again, this time selecting only the video stream instead of all tracks, and it demuxed w/o errors and the video stream is 29.970.

lol.. my version of eac3to most certainly is ancient b/c I don't normally use it, but you're right - I should (and will) update it.

Edit:
Do I need to change anything or is this OK?
Display aspect ratio : 3:2
Original display aspect ratio : 4:3

[Columbo]

Where did you see that and for which file?

[dennbenn]

Where did you see that and for which file?

It's what is shown in the MediaInfo report of the mkv remuxed by MKVToolNix. I fixed it (or so I thought) by manually adding 15/11 in the aspect ratio field of video properties. Then I realized that I wasn't sure if 4:3 is SAR or DAR, or if 3:2 is supposed to be DAR - which is what I want. The eac3to GUI image says 4:3 and the command line reports 3:2. How do I determine which one is DAR?

[Columbo]

In MKVToolNix, set the video track’s aspect ratio to 4/3 and remux. Then check that MediaInfo shows Display aspect ratio 4:3. Done.

Tech notes: Both values in MediaInfo are DAR. MediaInfo labels them that way literally:

Display aspect ratio = the DAR the MKV container is signaling (what players will use).
Original display aspect ratio = the DAR signaled inside the video stream (the MPEG-2 header).

3:2 is not a separate kind of ratio; it is just 720÷480. When the container DAR equals the frame’s width÷height, it means the container is declaring square pixels (PAR 1:1), which is wrong for DVD video. So 4:3 is the DAR you want, and 3:2 is the container value that needs correcting.

The quick check: compute width÷height of the frame. If the reported “DAR” matches that exactly, it is effectively the storage ratio with square pixels, not a real anamorphic DAR. MediaInfo’s Pixel aspect ratio line confirms it (1.000 means square pixels).

On terminology: in ffmpeg/x264 usage, “SAR” means sample (pixel) aspect ratio, not storage aspect ratio, which is a common source of confusion. The relation is DAR = (width÷height) × PAR.

About your 15/11: the MKVToolNix “Aspect ratio” field takes a DAR, and 15/11 is in fact a legitimate DAR. It is what you get from 720x480 with the ITU-R BT.601 pixel aspect of 10/11 (720×10 ÷ 480×11 = 15/11), where the 4:3 picture is defined as the central 704 pixels. So:

4/3: the generic interpretation (whole 720 width = 4:3). This matches the stream header and what most players and encoders assume.
15/11: the ITU-correct interpretation, slightly narrower picture.

Either is a valid DAR; 4/3 is what the source itself signals. After remuxing, MediaInfo’s “Display aspect ratio” should show whichever you entered (15/11 displays as 1.364).