Undocumented errors? Or I just missed it.(PTS Discontinuity

[Kijutsu]

While encoding a DVD video, I get a couple of errors that I haven't found documented anywhere and I don't understand them.

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No accelerated IMDCT transform found
[09:55:08] thread 17792112 started ("AC3 decoder")
[09:55:08] thread 18286800 started ("AAC encoder (libfaac)")
[09:55:08] sync: expecting 220651 video frames
Encoding: task 1 of 1, 0.00 %[09:55:09] sync: first pts is 25257
Encoding: task 1 of 1, 0.01 %[09:55:10] About to add iPod atom
Encoding: task 1 of 1, 25.59 % (43.66 fps, avg 38.01 fps, ETA 01h12m00s)
[10:19:55] sync: trashing late audio
[10:19:55] sync: trashing late audio
[10:19:55] sync: trashing late audio
[10:19:55] sync: trashing late audio
[10:19:55] sync: trashing late audio
[10:19:55] PTS discontinuity (212034052, 23314)
[10:19:55] sync: adding 50 ms of silence for track 80bd
Encoding: task 1 of 1, 31.92 % (37.31 fps, avg 37.55 fps, ETA 01h06m40s)
Encoding: task 1 of 1, 51.97 % (42.00 fps, avg 39.65 fps, ETA 00h44m32s)
[10:43:21] PTS discontinuity (218503575, 25257)
Encoding: task 1 of 1, 79.01 % (46.96 fps, avg 41.22 fps, ETA 00h18m44s)
[11:05:38] PTS discontinuity (223955963, 24468)
[11:05:38] sync: adding 50 ms of silence for track 80bd
Encoding: task 1 of 1, 91.08 % (43.83 fps, avg 41.14 fps, ETA 00h07m58s)
Encoding
Encoding: task 1 of 1, 91.61 % (44.53 fps, avg 41.15 fps, ETA 00h07m31s)

Would someone shed some light on these errors please? Thanks much!

Here's my system specs:

AMD64 3700+
A8V Deluxe
1 Gig of Ram
Windows XP
700+ gigs of Space

[jbrjake]

Would someone shed some light on these errors please?

PTS is the presentation time stamp: when a frame of audio or video should be displayed to the viewer.

That errors means there's a gap of more than half a second between two PTS markers on the DVD. This results in situations where MediaFork only has video in its buffer, and no audio. In order to keep audio and video in sync, MediaFork is adding 50 milliseconds of silence to the audio at these points--so it has something to write to file during the PTS discontinuity.

[Kijutsu]

So it's likely the video is buggered up somewheres?

[jbrjake]

So it's likely the video is buggered up somewheres?

I dunno, you'll have to watch and see for yourself.

I'm not sure it really indicates anything's buggered up, as much as a difference between how PTS works on a DVD versus when you're dealing with mpeg-4 and muxing. I think a DVD can simply say "hey, no audio for the next second" and it'll hold off that long before delivering the next sound packet. But when MF is encoding this stuff and multiplexing it on the fly, it depends on regular PTS markers to keep everything in sync (really, this is all happening in a source file called sync.c).

So instead of denoting silence by not having any audio packets when there's no sound, MF will denote it by having audio packets, just filling them with silence.

Hopefully, it shouldn't be perceptible as it's just two different ways of delivering "nothing" to the viewer.

(I do know that last year, titer loosened the sync code a bit in response to the Madagascar DVD, which had longer PTS gaps than most DVDs...)

[Kijutsu]

Would it help to run DVD shrink and rip the video to the harddrive before encoding with MF?

[jbrjake]

Would it help to run DVD shrink and rip the video to the harddrive before encoding with MF?

Dunno. You'll have to try it and see. I'd think probably not, but who knows? It could work.

[Kijutsu]

Thanks for all the info!