I've got some DVD rips which appear to be variable frame rate. As far as I'm aware, this is impossible, and yet it's what I have.
I rip the DVD using MakeMKV. I then extract the timecodes from the resulting MKV, and the timecodes appear to alternate betweem 50ms and 33 or 34ms timings:
So that appears to me to be variable frame rate, and this is how it's been ripped from the source DVD.
This source video plays just fine. The video is interlacd and I'm trying to deinterlace it with QTGMC. However doing this produces a fixed frame rate video with the audio randomly out of sync. It's out of sync in such a way that you can't compensate with a delay - the timing shifts randomly throughout the video.
If I use FPSDivisor=2 with QTGMC to produce a video with the same number of frames and the same framerate as the original, and then remux the timecodes file from the original footage back into the new encode, then the new video with the original timecodes plays just fine with the audio correctly in sync. It also looks decent. I'd be happy to go with this for my encodes, except this manual step of remuxing the original timecodes is a bit longwinded when you have several hundred encodes to process.
And I can't help but feel that this is a mistake and there's something else I'm missing. This is animated footage, and I notice mediainfo reports the frame rate as:
Frame rate mode : Variable
Frame rate : 24.769 FPS
Original frame rate : 29.970 (30000/1001) FPS
So I'm wondering if there's some IVTC that needs doing as well? I've scanned the footage and it does seem to be a mix of interlaced and progressive frames, however there doesn't seem to be a fixed pattern to it (which is why I ended up using QTGMC). Some sections have no interlaced frames at all, some sections have 1 frame out of 5 interlaced, sometimes 3 or 4 frames in a row are interlaced. It doesn't help that the source framerate is such an odd number as well, although I wonder if this is just the result of averaging the weird timecode values that are present. I also noticed a slight discrepancy between this source FPS, and the result of my encode with FPSDivisor=2, which has a reported FPS of 24.770
Any suggestions as to what the heck is going on here, and/or how I can stop QTGMC from breaking audio sync, would be most welcome!
I rip the DVD using MakeMKV. I then extract the timecodes from the resulting MKV, and the timecodes appear to alternate betweem 50ms and 33 or 34ms timings:
Code:
# timestamp format v2
0
50
83
133
167
217
250
300
334
384
417
467
501This source video plays just fine. The video is interlacd and I'm trying to deinterlace it with QTGMC. However doing this produces a fixed frame rate video with the audio randomly out of sync. It's out of sync in such a way that you can't compensate with a delay - the timing shifts randomly throughout the video.
If I use FPSDivisor=2 with QTGMC to produce a video with the same number of frames and the same framerate as the original, and then remux the timecodes file from the original footage back into the new encode, then the new video with the original timecodes plays just fine with the audio correctly in sync. It also looks decent. I'd be happy to go with this for my encodes, except this manual step of remuxing the original timecodes is a bit longwinded when you have several hundred encodes to process.
And I can't help but feel that this is a mistake and there's something else I'm missing. This is animated footage, and I notice mediainfo reports the frame rate as:
Frame rate mode : Variable
Frame rate : 24.769 FPS
Original frame rate : 29.970 (30000/1001) FPS
So I'm wondering if there's some IVTC that needs doing as well? I've scanned the footage and it does seem to be a mix of interlaced and progressive frames, however there doesn't seem to be a fixed pattern to it (which is why I ended up using QTGMC). Some sections have no interlaced frames at all, some sections have 1 frame out of 5 interlaced, sometimes 3 or 4 frames in a row are interlaced. It doesn't help that the source framerate is such an odd number as well, although I wonder if this is just the result of averaging the weird timecode values that are present. I also noticed a slight discrepancy between this source FPS, and the result of my encode with FPSDivisor=2, which has a reported FPS of 24.770
Any suggestions as to what the heck is going on here, and/or how I can stop QTGMC from breaking audio sync, would be most welcome!