[FFmpeg-user] Streaming a copy of a WebM file results in a VLC parser error and mkvinfo error reports.

[spaceduzi]

Hi,

I wanted to stream a WebM file with ffmpeg command [1] to a streaming
server implemented on top of boost:asio, but I noticed the following
problems.  When I dump the complete payload from the POST request,
there's some data in front of the EBML header.  And if I remove that
data with help of hexeditor, then mkvinfo reports error [2].  VLC
reports timing problems in both audio/video and exits with MKV/Ebml
parser error.  I noticed this on all my WebM test files.  Does this
sound familiar to anyone?

I tested with git commit [3] and with the 0.8.3 Ubuntu package.
ffmpeg options "-v 9 -loglevel 99" did not report any problems.
The streaming server that I use works perfect with test data sent in
POST requests.  And those timing issues in VLC were also present in a
setup with stream-m.

I prepared a tar package available at [4] containing a dump from the
POST payload w/wo the data in front of the EBML header and the
original file.

[1] $ ffmpeg -re -i file.webm -vcodec copy -acodec copy -f webm
http://localhost:PORT/post_test/lunivac

[2] Error in the Matroska file structure at position
FILE_SPECIFIC_POSITION. Resyncing to the next level 1 element.
     Resync failed: no valid Matroska level 1 element found.

[3] 6226d104a327733ef8591148ba84ac8a6820bd04

[4] http://www.datafilehost.com/download-fad5bbae.html

br,

-spaceduzi