[Libav-user] How to decode arbitrary frame

Thomas zengaja at gmx.de
Fri Jul 19 09:18:03 CEST 2013

Am 19.07.2013 02:26, schrieb James Board:
> ------------------------------------------------------------------------
> *From:* Thomas <zengaja at gmx.de>
> *To:* "This list is about using libavcodec, libavformat, libavutil, 
> libavdevice and libavfilter." <libav-user at ffmpeg.org>
> *Sent:* Thursday, July 18, 2013 8:55 AM
> *Subject:* Re: [Libav-user] How to decode arbitrary frame
> >You can use avformat_seek_file() followed by avcodec_flush_buffers() 
> before av_read_frame() to jump to an arbitrary position in the Stream.
> Thank you.  That works.  But I have an question.  Will 
> avformat_seek_file()
> seek to the exact frame, or merely to the nearest key frame?  I'm coding a
> video editor and I need to seek to exact frames.  My input
> format, for now, are raw formats where all frames are stored in
> full such as rawuyvy, or raw422P.  Will avformat_seek_file()
> seek to the exact frame in those raw formats
I'm reading raw rgb and uncompressed v210 in avi container. Here it 
finds the correct frames when setting min_ts ts and max_ts to the same 
value. With mov files avformat_seek_file() doesn't seem to work.

> , and will it also seek to the exact frame if I use it on MPEG-type 
> formats?
I Diddnt try with interframe coded material, but i guess you can only 
search for I-frames and you will need to decode the whole GOP to process 
get to the frames inbetween.
> Thank you.
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