Is there a further compress between m4v and xvid avi

[RainbowDu]

I am interested in how to play m4v files through directshow. Today I download Ultra QuickTime Converter to convert m4v files to xvid avi. I found that the size of xvid avi file is much smaller than that of m4v files. It is very suprised, is there still some space to compress after xvid encoding?

I opened these two files(m4v file and xvid avi file converted from it) with UltraEdit, and found that both files include the the same frame headers(00 00 01 B6). But between two frame headers there are great differences. It looks like that Ultra QuickTime Converter compresses the content of each frame in m4v however keep all frame headers in the same time.

My suprises:
What's mapping algrithm from m4v to xvid avi files?
Is it possible to play m4v directly through directshow(employing xvid filter of curse)?

[celtic_druid]

You would just need an m4v parser filter (wasn't Gabest working on one?). For now you could use mplayer. Really though I would have thought that an m4v muxed to avi would be larger.

Ultra QuickTime Converter it sounds like maybe you are re-encoding mp4's to avi's. If so then there are already plenty of direct show mp4 parser filters.

[foxyshadis]

Real m4v? Or mp4 renamed m4v by itunes? (Sounds like the latter.) I think haali's registers m4v as a supported extension now, if not try just renaming it to mp4.

[RainbowDu]

Yes, it is m4v. I got it by encoding through xvid_encraw command line. I am very amazed too.

Since I want to try play meadia stream encoded by xvid encoder passed through internet, so they are seperated packets not a file. On the other hand, for the sake of "real time", it is not appricate to play after appending packets to a whole file.

I don't know how they do in stream meadia players.

[shon3i]

That is raw mp4 files and can't be played. These files must be converted to real mp4 files via mp4box or to mkv via mkvmerge, or with some tool to avi and than can be played