[MEncoder-users] removing duplicate frames from avi mp4 source file

[ted morris]

Per problems below with capturing mpeg4 through RTP/RTSP packets
with my Sony SNC-CH240 high res Net camera--

I discovered the issue is that there are vop start frames that are sent
within
the RTP payload immediately preceding vop I-frame group type frames.  I
looked at openRTSP code and what *might* be happening is that openRTSP
is assigning a time-stamp to the start-frame type, then assigning the next
timestamp to the I-frame. There appears to possibly be a dropped frame
between
the duplicate+ I-frame to preserve the desired framerate (15 fps).

Would anyone out there be able to suggest or recommend RTSP capture software
alternative that can run on linux to openRTSP? If there is a way to deduce
if
a frame is actually there but being tossed out during decoding the MPEG4
with
mencoder, I would very much like to hear any suggestions from the group.

thanks,
ted


On Thu, Sep 8, 2011 at 10:37 PM, L. Lee <llee040 at sbcglobal.net> wrote:

> Most of what I encode has to incorporate some kind of pullup, but when the
> duplicates are consistent, I can use "-vf framestep=2...". In other cases I
> force the  frame rate, such as "-fps 30000/1001 -ofps 24000/1001 -mc 0.1".
> That in of itself is not enough to accomplish pullup, but you might use the
> strategy if no pullup is required (maybe "-fps 15 -ofps 15" or something).
>
> Laine Lee
>
>
> On 9/8/11 8:27 PM, "ted morris" <ted.morris at gmail.com> wrote:
>
> > Greetings,
> >
> > I have these really big *.avi contained mp4 video files,
> > that were originally captured via OpenRTSP/live555 @
> > 15 fps. (1970x1440). x 1 hr .
> >
> > mencoder determines that there are duplicate frames
> > and then proceeds to encode the duplicates. Then, when playing
> > back the video, the video has these annoying little pauses
> > due to the duplicate frames -- and ofcourse makes the file
> > larger than it should be (~3 GB).
> >
> > I tried the -noencodeduplicat option but I get the same
> > result. I also use the -nosound option because
> > the videos don't have audio.(nor do I want it).
> >
> > I would prefer to still use lavc (ffmpeg codec) for my
> > processed avi file.
> >
> > Would anyone know a trick to get rid of the duplicate
> > frames?
> >
> > thanks for any suggestions in advance,
> >
> > t
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>
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