The purpose of idr_pic_id is vaguely specified in the H.264/AVC spec. The parameter idr_pic_id is signaled in the slice header of IDR picture only (i.e. if NAL type is 5).
On the one hand the standard of H.264/AVC clearly says:
“When two consecutive access units in decoding order are both IDR access units, the value of idr_pic_id in
the slices of the first such IDR access unit shall differ from the idr_pic_id in the second such IDR access unit.”
On the other hand the spec. says the following regarding to the syntax element idr_pic_id:
“When present in the primary coded picture and any redundant coded picture, the following syntax elements shall have
the same value: field_pic_flag, bottom_field_flag, and idr_pic_id.”
The above statements do not contradict each another since the redundant picture accompanying a primary picture is a part of the same access unit as the primary picture. As a result the main purpose of idr_pic_id is to distinguish redundant IDR picture from the primary IDR picture. Hence, if in a stream two successive IDR frames with same idr_pic_id are present and SPS parameter redundant_pic_cnt_present_flag is zero (common case) then the stream is non-compliant, usually one of the frame in the pair is discarded by a decoder.
It’s worth mentioning that in Restricted Baseline, Main and High profiles redundant_pic_cnt_present_flag must be 0. In other words in these profiles two consecutive IDRs sharing same idr_pic_id are illegal and a player can react in such case as it wishes (e.g. to discard the second frame or to play both, by the way Elecard and VLC players play both frames).
In Baseline profile Redundant Pictures are allowed (along with ASO and FMO) to enhance error resilience. Formally the redundant picture is a redundant coded representation of a primary picture, it commonly covers a part of the primary picture. By the way each primary coded picture may have up to 127 redundant pictures (i.e. a single access unit may contain up to 128 pictures including itself). Usually only IDR frames are accompanied by redundant pictures since a corruption in IDR frame corrupts the whole GOP. The redundant picture is to be decoded only if transmission errors are sensed in the primary frame.
As already mentioned the redundant picture does not have to cover the entire region of the primary picture (i.e. the redundant picture does not have to be a replica of the primary one). Redundant picture can cover some important region of the primary frame (usually called ROI – Region of Interest).
23+ years’ programming and theoretical experience in the computer science fields such as video compression, media streaming and artificial intelligence (co-author of several papers and patents).
the author is looking for new job, my resume
What i don’t realize is actually how you are not really much more well-liked than you might be now. You are so intelligent. You realize thus considerably relating to this subject, made me personally consider it from so many varied angles. Its like women and men aren’t fascinated unless it is one thing to accomplish with Lady gaga! Your own stuffs great. Always maintain it up!
Thanks a lot for providing individuals with remarkably breathtaking opportunity to read from this site. It is usually so pleasant and also full of a good time for me and my office friends to search your site no less than 3 times a week to see the fresh things you have got. Not to mention, we are actually satisfied with your powerful creative ideas you give. Selected 1 areas in this post are easily the most beneficial I’ve had.
certainly like your web-site however you have to take a look at the spelling on several of your posts. A number of them are rife with spelling issues and I find it very troublesome to inform the truth then again I’ll certainly come back again.
you are welcome to help (my email: slavah264@gmail.com). The problem is that this site is non-profit with the purpose to share knowledge and experience both for beginners and professionals.
i believe that sharing knowledge and experience for free would assist to integrate people from poor countries in the modern technology. i invest tons of my spare time in this site. i have tons of issues to prepare and to publish.
Your place is valueble for me. Thanks!…
This design is steller! You certainly know how to keep a reader amused. Between your wit and your videos, I was almost moved to start my own blog (well, almost…HaHa!) Great job. I really loved what you had to say, and more than that, how you presented it. Too cool!
Terrific work! This is the type of information that should be shared around the web. Shame on the search engines for not positioning this post higher! Come on over and visit my web site . Thanks =)
Thanks for some other informative website. The place else may just I am getting that type of info written in such an ideal method? I have a undertaking that I’m simply now running on, and I’ve been on the look out for such info.
Great line up. We will be linking to this great article on our site. Keep up the good writing.
Thanks , I’ve just been looking for info about this subject for ages and yours is the best I have discovered till now. But, what about the conclusion? Are you sure about the source?
I have been browsing online more than three hours today, yet I never found any interesting article like yours. It’s pretty worth enough for me. In my view, if all webmasters and bloggers made good content as you did, the web will be a lot more useful than ever before.
you are an outstanding person if you find the paper on idr_pic_id of H.264 interesting