MPEG2 in Vegas

TimothyJinx

TimothyJinx

Well-known member
Count me as one of the confused.

I typically render in Vegas using the following preset:

DVD Architect 24p NTSC Widescreen Video Stream
along with an AC-3 file.

Now, we are supposed to render to an MPEG2 file with audio included. So, I tried the following:

Using the same preset but checking the "Include audio stream" checkbox.

When I do this my final render ends up with the video and audio out of synch. The synch problem occurs also whenever I use any of the other presets except for "DVD NTSC" which defaults to having audio included. This setting seems to be my only option.

What are you other Vegas users doing? I'm not opposed to buying some sort of conversion tool. I just want to upload in the proper format.
 
TimothyJinx said:
Using the same preset but checking the "Include audio stream" checkbox.

When I do this my final render ends up with the video and audio out of synch. The synch problem occurs also whenever I use any of the other presets except for "DVD NTSC" which defaults to having audio included. This setting seems to be my only option.
Click to expand...

I'm doing just what you did, but I don't see/hear any sync problems. Hmmm....

-> Maybe try it with out the pulldown added? (On the Video tab when going Custom) <- Worth a shot.
 
I haven't experienced any synch issues either.
How are you evaluating the rendered MPEG-2 file (Windows Media Player, Software DVD Player, Set-Top DVD Player)?
Are you experiencing these synch issues on the final DVD?
What program are you using to author the DVD?

I've found it best to burn a test DVD and evaluate the output on a set-top DVD player as opposed to review the render using a software player or from within the authoring program.

Also, I've had no problems importing MPEG-2 files rendered as elementary streams (separate m2v and ac3 files) into programs like DVDA, DVD-Lab, etc. If you don't have synch issues using this method, I don't see any reason not to use it.
 
Jive, first I've never understood the elementary streams, and why to go that route ... unless it simply saves a step in having to render out the AC3 seperately ... but I also don't know what m2v is, unless it stands for MPEG2 Video only.

Lastly, I had this Q in the content upload thread for Sci-Fest: When rendering out the MPEG2, there's a drop down box on the CUSTOM VIDEO page that defaults to DVD ... but if you look at the other options in there, there's also a MPEG2 (which is what I'm rendering anyway).

The help menu defines the DVD option as DVD compatible MPEG2 files, while the MPEG2 option is just defined as General MPEG2. Is there a benefit of choosing one vs. the other? If the MPEG2 option is better for this batch process (to FLASH, I'm assuming) that Jarred's going to do, then I'll go that route .... otherwise, I'll go with the trusty DVD default, as that's where the file will ulitmately end up anyway.
 
I render to elementary streams because some authoring apps require it (DVD-Lab, etc.). It also makes it easier to re-render the audio or video stream without having to re-render both streams or demuxing your original MPG file.

A m2v file is an MPEG-2 video stream.

The MPEG-2 codec is not only used for DVD-video. This is why the DVD compatible option is important as it makes the necessary settings for it to play properly on set-top DVD players. So if you want to render MPEG-2 for DVDs, then you should render it as DVD compatible.
 
David Jimerson said:
What's wrong with just using DVD NTSC?
Click to expand...

Well, I guess I'm confused about the expected average bps. Isn't it supposed to be 8M? It seems like if I change it then I get the synch errors.
 
Jive,

I'm just playing the rendered file using Windows Media Player. The video seems to be moving much faster than the audio. I haven't burned a DVD - I'm just trying to create a file to upload.
 
Playback on any computer system is very dependent on the system itself. If it can't properly handle playback (due to system resources, inefficient decoding, etc.), the audio/video may lose synch.

Does the audio gradually get out of synch, or is it out of synch from the very beginning? When you pause playback, and then unpause, is it still out of sych?

At any rate, if a setting works for your purposes (whether it be delivery on DVD or uploading), I'd say run with it.
 
Jive,

It's out of synch immediately.

I guess I'll just render using the DVD NTSC option, upload and hope it is acceptable.

Thanks everyone for you help.

TJ
 
Ok. Here is where I am at this point.

I select the "DVD Architect 24p NTSC Widescreen Video Stream" preset and then go in and check the "Include Audio Stream" checkbox and set the Max bps to 9,800,000 and the Avg bps to 8,000,000. No other changes. This preset is set to:
720x480, 23.976fps + 2-3 pulldown, 16:9 display. (I don't really understand any of the other settings).

As I stated earlier, the audio plays back correctly but the video ends up looking like 4:3 and moves along really fast when previewing using Windows Media Player.

But, when I preview using PowerDVD everything looks and sounds great (well, as great as it can look considering the source material). Everything is synched up, the picture is 16:9.

The file will not play through Quicktime.

How can I be sure the file is acceptable?

Thanks.
 
WMP has problems playing MPEG-2 files but is generally ok when playing it off DVDs (provided you have the proper codec).

If it plays fine in a software DVD player (e.g. PowerDVD), then you should be ok.

However, your max bitrate is way too high if you were to include it in an authored DVD as it can cause problems with set-top DVD players. You want to limit your max bitrate to 8 Mbps. In any case MPEG-2 plateaus at 8 Mbps, so you're not getting any better quality if you render at 9.8 Mbps than if you render at 8 MBps.
 
Jive, in programs like DVDA3, can't you just set the properties for what it's to render at (i.e. 6, 8, 9.6, etc.)? I always go with the DVD Architect MPEG2 setting, which has the max at 9.6, average at 8, low at 6, etc. If they have those as the default, I'd think it would be okay.
 
Interesting. If you're referring to the MPEG-2 Render Templates in Vegas, then my default templates are very different from yours.

All of my DVD Architect render templates list the following:
Maximum (bps): 8,000,000
Average (bps): 6,000,000
Minimum (bps): 192,000

Are your default templates different? I know I haven't modified them on my system because I mostly stick to my own CBR templates.

As for the maximum safe bitrate for MPEG-2, I'd definitely recommend googling around a bit. Most will recommend a maximum of 7.8 Mbps, and many recommend as low as 6 Mbps. I've had no problems thus far at 8 Mbps, so that's why I recommend it.

Also note that if you're using PCM audio (as opposed to AC3), then your maximum video bitrate needs to take that into account. As I understand, the DVD spec states that set-top DVD players must be able to play a maximum of 10.08 Mbps (including Video, audio, subtitles, angles, overhead, etc.). Even still, most DVD players cannot handle this data rate so the recommended max is closer to 9.8 Mbps (and even that's pushing it). With PCM audio having a bitrate of about 1.5 Mbps, that leaves only about 8.3 Mbps for everything else (video, subtitles, etc.), so even at 8 Mbps, your cutting it pretty close (if you're using PCM audio that is).
 
SOS!

Ok...I thought I was ready to roll.
Apparently not just yet.

Someone please explain the process for adding audio to a
DVD Architect NTSC Widescreen video stream.

Because every time I click "Include audio stream", the
template is changed back automatically to default.

I also tried rendering in DVD NTSC (and had audio) but the
ratio is not quite ready for primetime (per the guidelines).
 
Don't have that prob when I do it... Hmmm....

What about checking the Inlcude box first, then going in and changing the bitrate?
 
Nothing seem to work...

It says in the description box:
Audio: None
Video: 29.97 fps, 720x480
Use this setting to create an NTSC Widescreen video-only MPEG-2 file compatible with DVD Architect.
 
Thanks, GenJerDan, but still no dice.

Jarred was kind enough to give us till Friday to
upload. I'm gonna get some shut-eye. I wanted
to submit ASAP, but I'll just do it in the morning.
 
Oh. Oh. Oh. Ignore the Description Box! That stuff won't change unless you change it. That's for you to put notes in so you know what you've saved (if you save the changed preset under a new name). It doesn't automatically change when you change stuff.
 
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