Chapter markers 29.97/30fps problem using MeGui/Avisynth

[FeB]

Hi, I need help on a problem!

Testing a MKV h.264 file created by MeGui/Avisynth, I found that the chapter markers are in the wrong place.

For example, in the NTSC DVD "Kid Abelha - Acustico MTV" (from brazilian MTV Unplugged series):

- When I play the DVD on my Sony Blu-Ray player, the total duration of the main title indicated by the Bly-Ray player is 01:10:31 (hh:mm:ss) and chapter 21 starts on 01:06:57

- I encoded this DVD using HandBrake, and playing the HandBrake's M4V file using QuickTime Player 7 it tells me the video has 59.94fps, the total duration is 01:10:35.26 and chapter 21 starts on 01:07:01.88 (chapter 21 is starting at the exactly same position as the DVD played on the Blu-Ray player)

- The Megui/Avisynth's MKV file played on QuickTime Player 7 with Perian has 59.94fps, the total duration is 01:10:35.27 and chapter 21 starts on 01:06:57.87 (chapter 21 is starting in the wrong position, about 4 seconds earlier where it should be)

- The Megui/Avisynth's MKV file played on the Sony Blu-Ray player on a usb pen drive tells me the total duration is 01:10:35 and chapter 21 starts on 01:06:57



Conclusion: The Blu-Ray player is playing the DVD using 60fps and not 59.94fps, so the total duration is 4 seconds shorter because the video plays faster in 60fps than in 59.94fps.

HandBrake and MeGui/Avisynth encode to 59.94fps.

HandBrake puts the chapter markers on the correct positions, MeGui/Avisynth not.

Then I went to the MeGui's option Tools/Chapter Creator: I selected the option "From Disk", then I selected the VIDEO_TS folder directly from the DVD drive, then appeared a window with the three DVD's titles and asking me to choose one of them and I choosed the first one which says "VTS_01 - PGC 01 - 01:10:31.178000 - [21 Chapters]", then I clicked on the "Save" button.
This gave me a .txt file with the time position and name of each of the 21 chapters.
In this .txt file is written "CHAPTER21=01:06:57.878".
Well, this is the chapter 21 time position when played using 60fps and not 59.94fps, but MeGui/Avisynth gives me a 59.94fps h.264 video, so chapter 21 (and all other chapters) are on wrong position.

What can I do to create a MKV h.264 59.94fps video with the correct chapter markers time positions using MeGui/Avisynth?

[FeB]

I guess I found a way:

- Encode the DVD using HandBrake (must be to M4V file), I can use a super fast preset (for example, "Normal" preset with x264 preset changed to "ultrafast", all video filters off, video size changed to half or 1/4 of original size) which will encode 1 hour of video source in few minutes

- Open the HandBrake's M4V file on Metadata Hootenanny for Mac OS and then save the M4V's chapters in a .txt file with MKV format

- Use the .txt file in MeGui "Chapter File" option (instead of using default option "<internal chapters>").

I will make a test to see if it works.

[Zathor]

Are you able to upload a sample file? I would like to reproduce it.

[FeB]

Originally Posted by Zathor

Are you able to upload a sample file? I would like to reproduce it.

Hi, Zathor!

This is not a problem in the h.264 video stream, but in the chapters markers time positions. And also there is no video/audio sync issue.

With a small sample you would not be able to notice it, since the error becomes noticeable only after minutes of video.

I can't upload minutes of copyrighted video.

The error in chapters positions is:

((60000/1000fps / 60000/1001fps) - 1), which is equal to
((1001/1000) - 1), which is equal to
(1.001 - 1), which is equal to
0.001, which is equal to
0.00001%

So:

- In 1 minute (60 seconds) of video, the error in chapters positions is only 60 seconds * 0.001, which is equal to 0.06 seconds.

- In 17 minutes of video, the error in chapters positions becomes more noticeable, about 1 second of error

MeGUI puts inside the 59.94fps (or 29.97fps) h.264 output the chapters positions as if the video was going to be played at 60fps (or 30fps).

I guess it doesn't affect PAL DVDs because in PAL there is no dual fps (for example, there is no 24.97fps versus 25 fps). PAL is just 25fps, there is no 24.97fps.

I'm just playing the NTSC DVD "ABBA in Japan" here and:

- My Sony Blu-Ray player plays the DVD using 60fps, not 59.94fps, so chapter 14 ("Thank You for the Music" song) starts on DVD at 00:50:00 (hh:mm:ss)

- On the HandBrake M4V's 59.94fps file, chapter 14 starts on 00:50:03 which is 3 seconds later, but since the video reproduction is also 0.00001% later because it plays 0.00001% slower in 59.94fps than in 60fps, the HandBrake M4V's chapter 14 starts exactly in the same video position as when the DVD is played on Blu-Ray player

(all my DVDs are the originals, not DVD-R copies or pirates)

Well, it's interesting that my Sony Blu-Ray player plays NTSC DVDs using 60fps and not 59.94fps...

So, what's the correct fps to playing NTSC DVDs?

59.94fps?

Or 60fps?

Maybe Sony is wrong and the rest of the world is correct...

[FeB]

Originally Posted by FeB

I guess I found a way:

- Encode the DVD using HandBrake (must be to M4V file), I can use a super fast preset (for example, "Normal" preset with x264 preset changed to "ultrafast", all video filters off, video size changed to half or 1/4 of original size) which will encode 1 hour of video source in few minutes

- Open the HandBrake's M4V file on Metadata Hootenanny for Mac OS and then save the M4V's chapters in a .txt file with MKV format

- Use the .txt file in MeGui "Chapter File" option (instead of using default option "<internal chapters>").

I will make a test to see if it works.

I made a test, and yes, it works!