ffmpegX MPEG Keyframe interval Key to QT & DVDSP!

[TugBoat]

Damn.
So, as I've stated before, I've always had problems with ffmpegX encoded MPEGs in DVDSP2. I think I've found the answer.

First, see my posts here;
https://www.videohelp.com/forum/viewtopic.php?t=237571

The 4 movie DVD I made was rushed to evaluate how it worked on set-top DVD players. I had not included chapters as they are time consuming and I rushed out a DVD-RW. I then went back into DVDSP to create chapters and once again ran into extreme sluggishness and the eventual Spinning BeachBall Of Death. Damn.

I played around and the thought struck me that DVDSP was looking for I-frames and that was causing the SBOD. The default setting for I-frames in the preset I was using was 240! According to what I've read in the DVDSP manual, each GOP (which is about 15 frames) should have an I-frame. 240!!!!!

Well, I re-encoded the clip that was killing DVDSP with the Keyframe interval set to 14. NOW IT WORKS FINE. DAMN.

Not only that, it also fixed the sluggishness in the QuickTime Player and VLC. Damn.

This is one of the reasons I never used ffmpegX for MPEGs bound for DVDSP, they didn't work well in DVDSP or my set-top DVD Players. Well, now I have to re-encode the 6.5 hours of video on that DVD and try it again

++++++++++++
Yea, yea. RTFM. yea, yea...
Select the interval between I-frames or keyframes. I-frames need more data to encode the picture. Seeking is only possible to a keyframe. Don't use values higher than 300 for MPEG-4 and XviD, as quality can be affected. MPEG-1 and MPEG-2 should always use 12.
It would be nice if MPEG-1&2 presets included that setting....

[midwich]

Sounds like critical information, I just need to get my head around it! I've taken a copy of your post for safe keeping, cos it looks like I'm going to need this, just as soon as I find where I frames are dealt with in DVDSP. Anyway, this is a quick note to say that I'll be back with more info soon, am looking for a complete idiot's guide to DVDSP at the moment

[thoughton]

Nicely done TugBoat (or maybe we should be calling you Sherlock )!

So to clarify: these Half D1 clips were fine in DVDSP until you wanted to add chapters? And then you got beachballed? But if you set the I-frame interval to 14 they became DVDSP-friendly? Or was it 12 like the manual said?

Again, good info. Thanks for posting it.

[TugBoat]

Yea, I looked at the settings and the only presets affected are the ffmpeg MPEG-1 and MPEG-2 selections. Apparently, mpeg2enc does like most other MPEG encoders and automatically sets the interval. I just assumed ffmpeg was making mpeg complaint files by default

Basically, anytime you tried to navigate the timeline in DVDSP you'd got beachballed. But it only got stuck in certain places, like, eternally spinning and having to force quit. The dead giveaway was when I hit 'M' (to place a marker), and saw the marker appear seconds from where I wanted it. WTF?

Then, I had already converted all the files to a 14 frame Keyframe setting before I found the note about setting it to 12
The files worked fine navigating the timeline with the KF set at 14, but two files were causing the muxing to die during build. Soooo, I converted all the files (6 m2vs) to a Keyframe setting of 12.... letterboxed 4:3 aspect. All the movies are originally 16:9. Then, I found out how to do Half DVD at 16:9 Where's the 'beats head against wall' emotiocon?

Final Chapter? All files were converted to Half DVD, Keyframe 12, 16:9. It's a good thing ffmpeg encodes as fast as it does. That DVD has been burnt for the last time. Now I'm working on a three movie DVD and two of those movies had out of sync audio come out of ffmpeg. In sync at first, out by a .5 to 1 sec at the end. I used QT to export an AIFF from the original and that synced perfectly in DVDSP. Now what....


BTW.
One of those two movies that produced out of sync audio was done yesterday as 4:3 with 'Decode with QuickTime' enabled. That encode produced in sync audio. I trashed that build and encoded as 16:9 without 'Decode with QuickTime'. The one encoded without QT was the one out of sync. So....
8)

[major]

Yea, I looked at the settings and the only presets affected are the ffmpeg MPEG-1 and MPEG-2 selections. Apparently, mpeg2enc does like most other MPEG encoders and automatically sets the interval. I just assumed ffmpeg was making mpeg complaint files by default )

MPEG-1 and MPEG-2 should always use 12.
It would be nice if MPEG-1&2 presets included that setting....

ffmpeg VCD, ffmpeg SVCD and ffmpeg DVD does use a default keyframe interval of 12.

[TugBoat]

mmmmm,
So there's something wrong with my ffmpegX 0.0.9p? Because when I open it, select a file, select either 'MPEG1 [.MPG] (ffmpeg)' or 'MPEG2 [.MPG] (ffmpeg)', then go to 'Options'... it says 'Keyframe interval: 240'. And if I encode it like that, then take it to DVDSP 2.05.... well you read the thread
If I manually change it to 15, 14, or 12, everything's fine. I'll trash the prefs and restart, but I'm not going to hold my breath.

**********
Didn't help, still says 240 8)

**********
OK, if you choose one of those 3 special presets,
ffmpeg VCD, ffmpeg SVCD and ffmpeg DVD
it does go to 12, BUT, if you get to ffmpeg MPEG-1 or 2 any other way, it doesn't. It stays at 240. I also checked 0.0.9a that's on my PowerBook, it stays at 240 no matter what you choose, you have to change the interval manually.
Recently I've been choosing DVD-lo, changing the selection to ffmpeg and then making other settings, but not changing the interval. That's where the recent problems came from. You can fix that real easy right

[major]

mmmmm,
So there's something wrong with my ffmpegX 0.0.9p? Because when I open it, select a file, select either 'MPEG1 [.MPG] (ffmpeg)' or 'MPEG2 [.MPG] (ffmpeg)', then go to 'Options'... it says 'Keyframe interval: 240'.

You should use the Quick presets at the bottom to set all options automatically.

Or select the codec manually, and set all other options manually (when you open ffmpegX keyframe interval is set to 240 by default, as the default preset is mpeg-4).

But I will add an auto-setting of keyframe interval when selecting a codec manually, if it can save errors.

[TugBoat]

I think an automatic setting that would make many people's first DVD video track MPEG compliant would be an excellent idea. I don't consider myself a noob and I just now found out why my ffmpegX MPEGs didn't work right. Mention I-Frame Setting to many people and they'll look around at the walls trying to figure out which Picture has an iFrame :P