Vid flicker every 24 frames on MP4 29.97 render

Jasper Bluto wrote on 1/15/2009, 1:57 AM

I have to encode video for a client to these specs, to be posted on the website iAmplify:

VIDEO:
File Format: Mp4 (Basic - NOT Mp4 ISMA)
Video Format: H.264
Data Rate: 1372 kbps/sec (Single Pass/CBR)
Image Size: 640x480 VGA
Frame Rate: 29.97 (this may change to 15)
Key Frame: Automatic

AUDIO:
Audio Format: AAC-LC (Music)
Data Rate: 128 kbps
Channels: Stereo
Output Sample Rate: 44.100 kHz
Encoding Quality: Best

I'm starting with VOB files pulled from the client's own DVD.

When I playback the TL in Vegas, everything is perfect. When I play back the rendered MP4 file, I get a flicker every 24 frames. I looked at the rendered clip in Vegas and the 25th (1st?) frame is blotchy looking, with no detail. over the next 20 frames or so, the detail creeps back little by little and by the time the 24th frame cycles around again the video looks fine, only to repeat the cycle.

I checked the SCS website - I can't even BUY a support plan for Vegas 6.0 !
How messed up is that? Please, I really hope someone has seen this before and can help me out. I'll send you cookies.
Thanks
JB

Comments

farss wrote on 1/15/2009, 2:35 AM
Tricky one this.

There's a couple of bits of info that seem to be missing.

I gather from your comment about support you are doing this in V6.0?
If so it might be time to upgrade. I can't say for certain but I'd expect some improvement in the H.264 encoder in the last few years.

Secondly, Encoding from what? What frames per second. I assume as you've pulled this from the clients DVD it is interlaced? Of course starting from what's on a DVD is never a good things.

Thirdly, in the specs for the H.264 how many keyframes?

Lastly 1372 Kbps is a pretty low bitrate. It might be OK or it might not depending on the content.

Bob.
Jasper Bluto wrote on 1/15/2009, 9:55 PM
Bob, thanks for having a look at this. Here is some more info:

>>"I gather from your comment about support you are doing this in V6.0?
>>If so it might be time to upgrade. I can't say for certain but I'd expect some >>improvement in the H.264 encoder in the last few years."

I would love to upgrade. It's my understanding that Sony shut the door on that and I would now have to just buy it outright at full price. I just can't.

>>Secondly, Encoding from what? What frames per second. I assume as you've >>pulled this from the clients DVD it is interlaced? Of course starting from what's >>on a DVD is never a good things.

Yes, it's interlaced video coming in at 29.97 and being rendered at 29.97.

>>Thirdly, in the specs for the H.264 how many keyframes?

I don't see any parameters in the mainconcept MP4 screen to adjust keyframes.
Does this info help at all?

JB










Lastly 1372 Kbps is a pretty low bitrate. It might be OK or it might not depending on the content.

Bob.
AtomicGreymon wrote on 1/15/2009, 10:23 PM
I would love to upgrade. It's my understanding that Sony shut the door on that and I would now have to just buy it outright at full price. I just can't.

I'm not sure what you mean by "shut the door"... upgrades to version 8 from past versions are available here:

http://www.sonycreativesoftware.com/upgrade/vegaspro?disp=1

Just out of curiousity, are you actually doing any editing to this video? Or are you just taking the original VOB, sticking it on the timeline and rendering out to H.264? Because if you just want the thing converted without any editing, there are other solutions... with better H.264 encoders than Vegas provides.

Handbrake is a freeware app, and I'm pretty sure it will take in VOBs (its primary function is going straight from the DVD). It encodes to H.264 for iPod... but an iPod compatible file is pretty generic. The maximum allowed bitrate of around 2500kbps should be more than enough to preserve your quality. H.264 can do impressive things at relatively low bitrates.
farss wrote on 1/15/2009, 10:28 PM
"I don't see any parameters in the mainconcept MP4 screen to adjust keyframes."

Indeed, my bad. Look for a parameter "Number of reference frames".
My last H.264 encode has 16 in that box. Set it too low and things get ugly, set it too high and some players can have problems not being able to buffer than number of frames. Somehow though this might not make a whole lot of difference.

I'd suggest you try doing this in two stages.

1) Render out to a DV AVI file first and check that for any oddities.
2) Then encode from that to H.264.

This is unlikely to fix the problem but it'll make it easier to diagnose.

What I find curious is that the problem you're having is occuring every 24 frames, that sounds kind of significant.

Bob.
bsuratt wrote on 1/16/2009, 3:38 AM
I would double check that original DVD is not actually 24 fps!
Jasper Bluto wrote on 1/20/2009, 12:38 AM
Grey Mon...
I can be pretty dense sometimes. I got email a while back from Sony saying that the upgrade window from 6 to 8 was ending... What I didn't realize was that they meant upgrading for $199 was ending. You are correct, I can - and did - upgrade to 8.0, it just cost a little more now.

Of course, now when I try to import any of my old Vegas 6 projects into Vegas 8 I get an error and it crashes. If I try to import a VOB (which 6 did with no problems) I get an error and it crashes. I F$#%ING HATE SONY. It could be worse... I could be using one of the other NLE's and hating every minute of it. At least when the Vegas is running, I can edit in my sleep. I have Adobe Premier CS3 and I would rather stab a fork in my eye than try to work on that software.

Anyways... If you or anyone is familiar with the VOB or old ver import crashes, I would really like to hear from you
THANKS!
JB
AtomicGreymon wrote on 1/20/2009, 8:01 PM
if you have the DVD this stuff came off, the best way to actually get the footage into Vegas is to use the "File --> Import --> DVD Camcorder Disc" method (provided this DVD isn't protected, in which case it won't work), in which Vegas runs through the DVD and imports all the VOB files.

Personally, though, I've had really uneven results trying to work with VOB files in my NLEs (I've got PPro CS3, as well). They just really weren't meant to work with that kind of footage, unless you count the MPEG-2 video used for HDV. But the stuff on a DVD is more difficult for them to work with, it seems.

I'm not sure about importing project files from past versions (I started using Vegas with 8), but I would've thought it would work.

Your best bet is to convert the VOB into another, easier to edit, format before working with it in Vegas. If you have the space, uncompressed AVI is the simplest and ensures you won't lose any quality.
Jasper Bluto wrote on 1/23/2009, 11:11 PM
Greymon and friends,
You folks are really cool for taking the time to help a newbie. I really appreciate it. I would up biting the bullet and upgrading to Vegas 8. Now, of course, it refuses to even import VOB files AT ALL. On the plus side, it renders MP4 beautifully.

I used AVS Video Converter to convert all the VOB files to AVI, then bring them in, but it's just a pain. I really would like to be able to just bring them right off the DVD into Vegas,.. snip snip... fade fade... title title... then render.

I'll see if Sony can fix this for me before my 9.2 milliseconds of customer support run out.