Transcoding wmv to MP4 on VideoLAN 0.96 on WinXP-SP3

[davodavo]

Having two problems with version 0.96 on windows. One is new, one has been around since at least 0.86.

Input file: "source.wmv" (I have all these files in a zip, but I can't figure out how to attach them here )
Output files: "test v96.mp4 (produced by VLC 0.96, showing latest audio and video artifacts)
. . . . . . . . . "test v86.mp4 (produced by VLC 0.86i, only video artifacts)
System: IBM x31 thinkpad with all the latest drivers, codecs, patches. Video device is 1024x768x16 LCD driven by ATI Radeon (driver 6.14.10.6547). Audio device is SoundMax (driver 5.12.1.5410)
Player software: iTunes 8.0.1.11 or QuickTime 7.5.5 or iPhone 2.1 or VLC 0.96
Transcoder settings: transcode to mp4 file, with mpeg4 video codec and mpeg4/AAC audio codec


Video problem: extreme pixelation and lack of image in first second or so of video. This is not in the original file, but is an artifact of transcoding. Appears to me to be equally bad in both test files. This appears in all players, and has been with us for at least six months. Didn't see any discussion of it, but the forum search engine is acting very flaky today.

Audio problem: this problem is new, and only shows up on all apple playing software. When playing the Test v96.mp4 file on the VLC player, all the audio is fine. But when playing the same file on apple players, the audio is extremely choppy, sometimes dropping out entirely. Seems to be some sort of a buffering problem, where the audio is coming too fast (somehow) for the apple players to keep up. Did experiments with bit rates from 96 to 192 kb/s, always the same effect. This was not a problem on v0.86i on the same hardware.

If you want to look at the input and output files (the whole smash is less than 6 MB) let me know how I can get the files to you.

[VLC_help]

You can for example use Rapidshare or Megaupload for file sharing. And paste the transcoding option also. But if you just want to change your video another format, I suggest AVIdemux. You can do two-pass encoding and get better quality/total size value.

[davodavo]

You can for example use Rapidshare or Megaupload for file sharing. And paste the transcoding option also. But if you just want to change your video another format, I suggest AVIdemux. You can do two-pass encoding and get better quality/total size value.

Ah, but that site (like most) requires that you identify specific people to be recipients.
So, here's my offer: I've posted the files on my website, so they should be downloadable by anyone who wants them (hint: developers

file location is http://www.taberconsulting.com/testfiles.zip

have at them, folks!

[VLC_help]

Could you also tell transcoding options you used?

[davodavo]

Could you also tell transcoding options you used?

input file was WMV

output container was mp4

audio was AAC, either 96 or 192 kbps

video was mpeg4 @ 1024 kbps (for vlan 0.86i) and 800 kbps (for vlan 0.96)

both input and output files were on my local disk

[VLC_help]

You are right. QuickTime doesn't handle the audio decoding correctly. And video encoding doesn't work on best possible way (it seems like it misses the first keyframe). There has been changes on AAC audio encoding on upcoming 1.0.0 that hopefully fixes audio issues.

[davodavo]

You are right. QuickTime doesn't handle the audio decoding correctly. And video encoding doesn't work on best possible way (it seems like it misses the first keyframe). There has been changes on AAC audio encoding on upcoming 1.0.0 that hopefully fixes audio issues.

Yeah, it's weird that v0.86i didn't have the AAC audio problem.

The video problem isn't just the first frame of the file -- it's the first frame of whatever you look at. So if you start playback in the middle of the file, all kinds of lovely artifacts are strewn across the frame.

[VLC_help]

0.8.6 didn't use as new codecs as 0.9.x does. Seeking issue should only bother VLC (because of the libavcodec issues). Seeking in QuickTime works OK.

[davodavo]

Update for everyone: I switched over to AviDemux for my video-to-mp4 conversion, under the advice of people in this forum. And it's a great tool...except it can't generate mp4s that can be played by an iPhone at all. It pretends to, but the video is blank.

So...please work on the codecs for VideoLAN because I'm depending on you

Thanks, and have a great holiday season.

[davodavo]

Hi all,
Tried VideoLAN 0.9.8, same problems with video codecs and initial visual artifacts.

Any clues about new / better codecs for VideoLAN?

[VLC_help]

You can always try nightlies.
http://nightlies.videolan.org/build/win32/?C=M;O=D