Passthrough export of XVID to M4V?

[davecool]

Hi all. I'm posting this in the Mac forum because I'm trying this on a Mac and I think Mac users will have more insight.

I've got some XVID encoded AVI files that I want to convert to M4V. Sure, I could just re-encode them, but I think there is (or should be) a better way.

Since XVID is just MPEG-4 video, shouldn't I just be able to demux the AVI and then mux the output files into an M4V? I've tried and it doesn't work. I'm not sure why. Using MP4box, I was able to directly convert the XVID to M4V (it has a built in feature for that), but QuickTime wouldn't open the file (it said incompatible file), but VLC played it. So, at least I know it's a valid file -- problem is that I want to make files that will play in iTunes/AppleTV.

Next I tried demuxing and remuxing. This actually worked. Sort of. The resulting file loaded into QuickTime player and was recognised as an M4V, but it wouldn't play properly. It would play a few seconds and then go blocky and then play normally and then go blocky and stutter, etc.

So, I guess, what I'm asking is this: Is there a way to make this work? Do I just need to figure out the right way to do it, or will QuickTime never play this file? Does XVID use settings that QuickTime can't handle? I know tha MPEG-4 is MPEG-4, but that QuickTime's implementation is lacking (at least for H.264, but I don't think XVID is an H.264 implementation).

Any thoughts? Should I try posting this in the conversion forum too?

Thanks!
David

[terryj]

First, Quicktime CAN and DOES handle XVID.
But, it needs the proper codec to do so.
Do you have Perian 1.0 codec installed in
your Library/Quicktime folder?

From Wikipedia:

Xvid is not a video format. Since Xvid uses MPEG-4 Advanced Simple Profile (ASP) compression, video encoded with it is MPEG-4 ASP video (not "Xvid video") and can therefore be decoded with all MPEG-4 ASP compliant decoders

which is why Quicktime's native MPEG-4 codec is having trouble.
You need Perian installed and then it should handle the XVID
decoding fine. From there, you should be able to
trasncode it to Apple's preferred flavor of MPEG-4
( sorry, yes you will if you want AppleTV/iTunes to not
have any problem with it ).

[davecool]

Thanks for the reply. It does play in QuickTime, I'm not having trouble with that. What I really want to do is just pass through the MPEG-4 video from the original XVID AVI file into an MP4/M4V container _without_ re-encoding it. It seems like this should be possible.

[terryj]

Thanks for the reply. It does play in QuickTime, I'm not having trouble with that.

then your earlier stament is misleading.

The resulting file loaded into QuickTime player and was recognised as an M4V, but it wouldn't play properly. It would play a few seconds and then go blocky and then play normally and then go blocky and stutter, etc.

to me, that means the file isn't playing properly, demuxed or not.

Have you tried the passthrough (video) option in ffmpegx to Mpeg-4?
what was the result of that?

[davecool]

Good thinking about using ffmpeg to passthrough the video. Sadly it didn't work either. Again, the resulting file stutters and goes blocky. I tried the same thing through VLC using the save option when opening the file. I output as an MPEG4 file and again no dice. (I think VLC gives the same results because it's built from ffmpeg, but I could be wrong).

When QuickTime plays the output files with stutter/blocks it reports that Perian is playing the file. I tried removing Perian from the QuickTime plugins folder to see what would happen. QuickTime Player then reports that the Apple MPEG4 Decoder is working, but then all I see is a white screen, no video at all.

I'm guessing the original XVID AVI was encoded with some options that QuickTime just can't handle. A direct copy of the MPEG4 video was a good thought, but I guess I'll need to just re-encode.

Thanks for your help,
David

[terryj]

Dave,
your welcome!
good luck and post back if you have further problems.

[jpschuck]

I'm guessing the original XVID AVI was encoded with some options that QuickTime just can't handle. A direct copy of the MPEG4 video was a good thought, but I guess I'll need to just re-encode.

Yes that's the problem. Quicktime only regognizes .MP4 using MPEG-4 Simple Profile (and, of course, H264/AVC*), while most XVID videos use MPEG-4 Advanced Simple Profile (which means advanced encoding options such as B-Frames, QPEL, etc). When importing the file with MP4box, you should get a message stating which level the video is using ; if I remember well, only level 1 and 2 are supported by Quicktime.

You can still play such .MP4 files in Quicktime Apps if you install an alternative MP4V decoder, but that doesn't help when it comes to the AppleTV.

*Well, actually, Quicktime is not able to read any H264/AVC encoded .mp4 either, because it doesn't support every AVC profile. There is also an alternative AVC decoder for Quicktime.

[live4ever]

Try MEncoder as well.
http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-streamcopy.html