[Libav-user] Seeking, timestamps, AVFrame, AVStream

James Board jpboard2 at yahoo.com
Mon Sep 16 18:50:58 CEST 2013

>> Yes, I looked at avcodec.h and could not find what I wanted.  When I was

>You wrote:
>    pts
>    pkt_pts
>    pkt_dts
>    coded_picture_number
>    display_picture_number
>    best_effort_timestamp (the name of this one really worries me)
>    pkt_pos
>    pkt_duration
>What do those all mean?  Can I use those to figure out which frame this is?
>All of these are documented there. That's why I thought you hadn't
>looked at the docs.

Actually, none of them (except pts) are defined there.  Most aren't
even mentioned.  But they are mentioned in AVFrame.h

>My gut feeling is that the biggest problem is that you probably need
>to read up on some basics, so the docs (which are quite OK IMHO) make
>sense to you, so you know what a timebase, presentation timestamp,

Yes, I definitely prefer reading docs then asking for help.  But what docs
are you talking about?  I'm not aware of anything other than the source code.

Anyway, it sounds like pts and best_effort_timestamp are really frame numbers
(not time values) and to get the actual time value, you multiple them by the 
time base.  Is that correct?  I'm actually starting with frame numbers and I 
don't really need the time values, per se.  Can I merely use the pts or 
best_effort_timestamp and assume they equal the frame number?

Also, will the libs do anything behind the scenes to duplicate frames for 
whatever reason (like to meet some CFR rate)?  I don't want that.

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