According to this GOP can have more than one I-frame.
According to wikipedia:
An I frame indicates the beginning of a GOP.
If every I-frame starts new GOP it implies one I-frame per GOP.
I believe that wikipedia is wrong. But I have also other questions. I found that:
each GOP is independant: all frames needed for predictions are contained within each GOP
If this is correct then it means that each GOP must start with key frame (I-frame which is also IDR). I saw contents in which they're not, so maybe assumption about GOP independence is incorrect.
So here are my questions:
- Can GOP have more than 1 I-frame?
- If #1 is "no" then why not all I-frames are key frames? Aren't GOPs suppose to be independent?
- If #1 is "yes" then must GOP at least start with IDR?
- Is there some format that has variable GOP length? I mean e.g. one GOP is IPP, second is IPPPPP and third is IPPP.
- What about content that has e.g. 600 frames. I 19*P, I 19*P (...) but has only one key frame (first I-frame). Does such content has GOP length 600 or 20?