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<DIV><BR>----- Original Message ----- <BR>From: Andy Shaules <BR>To: This list
is about using libavcodec, libavformat, libavutil,libavdevice and libavfilter.
<BR>Sent: Saturday, November 23, 2013 12:55 AM<BR>Subject: Re: [Libav-user]
packet flag AV_PKT_FLAG_KEY</DIV>
<DIV> </DIV>
<DIV><BR>On 11/22/2013 7:47 PM, Don Moir wrote:</DIV>
<DIV> </DIV>
<DIV>>>Not sure what AV_PKT_FLAG_KEY is supposed to mean. The assumption
to me early on is it represented a key frame but not necessarily.</DIV>
<DIV> </DIV>
<DIV>>>Is it not a application flag ?</DIV>
<DIV> </DIV>
<DIV>>>Seems for at least H264 it doesnt have much meaning to application.
If the packet dts value is in the stream index_entires then that represents a
key frame for sure ( hopefully :)</DIV>
<DIV> </DIV>
<DIV>>>What if there are no index_entries ? Whats a key packet then and
how to determine ?</DIV>
<DIV> </DIV>
<DIV>>>Just trying to clear up my own confusion with this.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>>For h264, the key frame network abstraction unit of the packet will be
of type IDR, instant data refresh. <BR>>I believe NAL type 5. </DIV>
<DIV> </DIV>
<DIV>Thanks Andy. </DIV>
<DIV> </DIV>
<DIV>Dont see that info in a packet. Only thing relevant that changes is
the flags member (0 or 1). Now frame may contain additional info after decoding
but it's documented that AV_PKT_FLAG_KEY represents a keyframe.</DIV>
<DIV> </DIV>
<DIV>If it is for internal use, a different flag should have been used the way I
see it. So trying to understand what the real intended use of AV_PKT_FLAG_KEY
is.</DIV></BODY></HTML></FONT></FONT>