[gst-devel] Different encoding behavior gstreamer/ffmpeg

[Albert Costa]

Hi all,
in my attemps to use gstreamer for dealing with mpeg2 ts files, I've ended up with following issues:
I'm willing to generate mpg2ts files that will be used for analysis whilst beeing generated (this is what ts is good for...). I also need to seek for a specific frame in the file (using external code).
I tried following things:

gst-launch filesrc location=myfile.avi ! decodebin ! ffmpegcolorspace ! ffenc_mpeg2video quantizer=4 gop-size=1 ! ffmux_mpegts ! filesink location=myfile.ts
This generates a mpg2ts file that I can read with gstreamer, windows media player (with haali splitter codec), but not VLC...

I tried similar thing using ffmpeg:
ffmpeg -y -i myfile.avi -copyts -an -vcodec mpeg2video -intra -qscale 4 -f mpegts myfile.ts
This should generate the same output, but it does not. Here I can read the output file with all media players.

More than that, using command line to seek&extract a frame:
ffmpeg -y -ss 0:4:0.0 -i myfile.ts -vframes 1 -f image2 test.jpg will seek (almost) correctly and get the frame with ffmpeg-generated file, but not with gstreamer-generated file.

I thought that gstreamer ffdec/mux plugins were based on ffmpeg, but it seems it doesn't have correct behavior. Has anyone experienced the same problems? Or could reproduce it? How can I know which version of ffmpeg the gst plugins are based on? Looks like the gst formating is not so well-formed...
I'm really stuck with that problem, and would like to get over it, so any hint is welcomed!

Best Regards,
Al

(my config: XP with winbuild-0.10.4)


      
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