[Libav-user] Reducing latency of file opening (when playing from http)

Bjoern Drabeck bjoern.drabeck at gmail.com
Fri May 10 04:06:54 CEST 2013

> > I was wondering if there is a way that I can reduce the
> > time it takes to open a file when I am playing it from
> > online.
> Did you test the -probesize and -analyzeduration options?
> Carl Eugen

Thanks for your reply, I briefly experimented with the -probesize
option, it seems to default to 5000000, and I brought it down to
100000, without any noticeable effect, so I have the following
questions for you:

1. What are the suggested settings for -probesize and -analyzeduration
if I am playing files from online?

2. I noticed when I opened one of those online files, it took around
14 sec every time I tried yesterday, however if I seek deeply into
that file, that is much faster, around 2 sec (I am under the (wrong?)
assumption that the operations would be fairly similar, ie start
reading from that location and build up a buffer, except when I am
opening a file it would also need to read header information). So is
there anything else I can do to help speed up the opening process,
other than the above two options? Can I affect that buffering behavior
 ie how deep it buffers?

3. Like I mentioned in another mail to this list (but no reply), when
I pause my player during playing an online file, after a while I
always seem get get a bunch of AVERROR_INVALIDDATA errors, it recovers
and later delivers correct packages again, but it results in a couple
of frames with artifacts, which I would like to avoid. Is that some
kind of disconnect inside ffmpeg? Maybe after some timeout or so? Can
I affect that behavior?


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