Help in transcoding Cinepak to MP4 with FFMPEG

[ClimbingAddict]

Hello,
I am currently seeking some help/advice as to settings to use in transcoding a video file into a MP4. Specifically my problem is that my output video file has some artifacts or noise of the previous frame (see attached picture, highlighed in red). The interesting issue is that the noise persists across the next few minutes, though the original source file does not have any of these artifacts.


I was hoping someone could give me some pointers as to settings or changes I should make in order to make sure I don't get this noise in my output file. Goal is to have a file with relatively good file size which can be played back on multiple platforms (Windows, Mac, Linux); as such I am ready to change codecs etc... however MPEG4 seemed like a good choice (I know I should resize the pictures, but this will happen at a later stage).

INPUT Video file details: The original file is a AVI encoded with Cinepak by Radius, composed out of JPG pictures at 1024*768, 5FPS.
This file was composed programmatically out of the original JPG images. Playing back the file frame by frame shows "clean" jump from 1 picture to the next one (as opposed to the artifacts left behing after transcoding w/ ffmpeg).

Here is my FFMPEG output and command line parameters used.

ffmpeg.exe -vcodec xvid -b 300 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ab 32 -i IR2.5fps.avi OUTPUT.xvid.mp4

ffmpeg version 0.5.0-pre2, build 613 Copyright (c) 2000-2005 Fabrice Bellard
configuration: --enable-mp3lame --enable-faac --enable-faad --enable-amr_nb --enable-amr_wb --disable-ffserver --disable-ffplay --enable-small --enable-memalign-hack --enable-gpl --enable-xvid --enable-dts --enable-a52 --enable-vhook --enable-pthread
built on Nov 13 2005 21:13:33, gcc: 3.3.1 (cygming special)
Input #0, avi, from 'e:\VIDEOCOMPOSE\IR2.5fps.avi':
Duration: 01:05:47.0, start: 0.000000, bitrate: 2787 kb/s
Stream #0.0: Video: cinepak, 1024x768, 5.00 fps
Stream #0.1: Audio: mp3, 22050 Hz, stereo, 56 kb/s
Output #0, mp4, to 'OUTPUT.xvid.mp4':
Stream #0.0: Video: xvid, 1024x768, 5.00 fps, q=2-5, 300 kb/s
Stream #0.1: Audio: aac, 22050 Hz, stereo, 32 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Stream #0.1 -> #0.1
Press [q] to stop encoding
frame= 1044 q=4.0 Lsize= 11719kB time=208.8 bitrate= 459.8kbits/s
video:7696kB audio:3929kB global headers:0kB muxing overhead 0.808316%

I would greatly appreciate any suggestions.
Sincerely

[celtic_druid]

Two things. XviD in VfW and mencoder has bframes enabled by default. For QuickTime compatibility you really need to limit yourself to SP only. Then again I don't know what defaults ffmpeg is using.

Not sure about now, but ffmpeg's mp4 output was broken. It wasn't outputting spec compliant streams. So you might want to try remuxing using yamb/mp4box.

[ClimbingAddict]

A few more details.
I've just tried playing back the original INPUT file in mplayer and I experience the same issue of artifacts on regular playback. When I playback the file in Windows Media Player, I do NOT experience the artifacts.

I'm guessing that since ffmpeg and mplayer share libavcoded??, I might always experience this problem when trying to re-encode the file.
I would appreciate any suggestions.

Suggestions on alternate tools to convert which can be scripted or used from the command line would be appreciated (not using ffmpeg).

At this point, I am also considering changing away from CINEPAK on the original AVI compose program. Does anyone have any suggestion on whether this might resolve the issue, recommendations on what CODEC to use ?

Thanks

[celtic_druid]

Well it does sound like libavcodec is not decoding the cinepak input correctly so switching to a different codec would seem like a good idea. I still don't think that ffmpeg outputs spec compliant mp4's though.