[vlc-devel] Re: Doing an lseek() with VOB files ...
John Michael Zorko
j.zorko at att.net
Wed Aug 13 10:18:42 CEST 2003
Thanks for your input.
> Does the server VLC start streaming on a I-Frame when doing ff/rewind?
> If not you get a jumbled-up video because you then have either a P or
> a B-Frame and they depend on previous frames.
The server does an input_Seek() to the off_t of a sequence header /
GOP. Since I-frames are the first frame in the GOP, this shouldn't be
an issue. The real issue here is that, when VLC is playing from a
file, seeking anywhere doesn't disrupt the video i.e. the seek bar in
the GUI does not seek on I-frames, it seeks to an off_t that represents
where the GUI bar was moved to, without regard to if this is an I-frame
or not. When playing from a stream, this same action (using the GUI
seek bar on the server VLC) results in momentary disrupted video on the
So, something is different when VLC is playing from a file and a seek
happens, than playing from a stream and a seek happens on the server
VLC. Either the data sent from the server to the client is different
in this case, or the code that the client VLC executes (the UDP access
module, the MPEG demuxer, the libmpeg2 codec interface, and the
video_output) is doing something different because it's a stream, and
this something different is resulting in jumbled video for a fraction
of a second every time the server VLC seeks, whether it's to an
I-frame, GOP, sequence header, pack header or random off_t. This is
what i'm trying to find.
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