Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Video Encoding > MPEG-4 AVC / H.264

Reply
 
Thread Tools Search this Thread Display Modes
Old 4th July 2012, 02:55   #1  |  Link
alexsmith
Registered User
 
Join Date: Apr 2012
Posts: 8
how to judge the key frame in h264 stream

Dear all,

Is there a simple way to judge whether a h264 frame is a key
frame or not?

If not, is there any document that I can use to solute this
problem?

thanks in advance,
alex
alexsmith is offline   Reply With Quote
Old 4th July 2012, 07:05   #2  |  Link
Dust Signs
Registered User
 
Join Date: Jun 2004
Location: Salzburg, Austria
Posts: 219
IDR pictures (NAL unit type 5) are always key pictures. I pictures can be key pictures, but do not have to be, since the pictures after it may be predicted from pictures coded before the I picture. Sometimes, recovery point SEI messages (NAL unit type 6 with SEI payload type 6) are present which indicate that I pictures are actually key pictures, but you can't rely on the existence of these SEI messages since they are optional.

Dust Signs
__________________
The number you dialed is imaginary. Please turn your phone by 90 and try again
Dust Signs is offline   Reply With Quote
Old 4th July 2012, 08:03   #3  |  Link
hello_hello
Registered User
 
Join Date: Mar 2011
Posts: 4,634
Aside from the above, of which I was blissfully unaware, ffdshow has "frame type" as part of it's on screen display. Of course you've got to play the video and stop it on the frame in question.....
hello_hello is offline   Reply With Quote
Old 9th July 2012, 03:25   #4  |  Link
Blue_MiSfit
Derek Prestegard IRL
 
Blue_MiSfit's Avatar
 
Join Date: Nov 2003
Location: Los Angeles
Posts: 5,930
You can also use ffdshow + DirectShowSource in AviSynth to get granular seeking.

I believe this method doesn't make a distinction between IDR pictures and I pictures, and simply calls them all I pictures.
__________________
These are all my personal statements, not those of my employer :)
Blue_MiSfit is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 08:52.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.