More keyframes for GoPro videos?

[c.fletcher]

Hi Guys here some footage...
[SV]mfsQGNOv5WY[/SV]
take care
Chris

 

[Geekhybrid]

Y'know, Matt - I learned about encoding keyframes here from what you posted, and you got my curiosity up. I've been looking at all the wiki's etc, but I'm not finding anything much related to h.264 keyframes. In fact, the wiki on H.264/MPEG-4 AVC does not even include the word "keyframe". Very curious. My YouTube Channel

If you read the first 3 or 4 points on the "Features" Features section of that Wiki, they are all basically describing "key frames". That term is largely disparaged in descriptions of codecs, I have found. I guess it inaccurately describes what's happening and leads to confusion like this. Though it does often appear when you are on the user side of things, for example in a settings dialog box in Compressor or outputting from an Avid. It's just easier to understand, I guess.

The I, B and P frames you mention later just describe the frame type for inter or intra frame comparisons being made in the compression algorithm. But in short, as you've concluded, H.264 and variants ie. MPEG4) do use "key frames".


See key frames for explanation of some of the terms in the Features section mentioned above.

I also don't know if any of this answers the OPs questions. I haven't seen a frame inaccurate editing system since the early 90s SVHS editors. Even editing with Quicktime Player Pro from 10 years ago, I could still be frame accurate.

Edit: It does occur to me that one time "key frames" has come up is when editing H.264 footage in FCP. Basically, your edit point slip and come in at random points. It has something to do with the way H.264 encodes, tough I can't remember how, exactly. The solution is to trans-code all your H.264 footage to Apple ProRes, if that's the issue.

 

[CriticalMass]

If you read the first 3 or 4 points on the "Features" Features section of that Wiki, they are all basically describing "key frames"..... See key frames for explanation of some of the terms in the Features section mentioned above.

To be clear, I wasn't looking for information on keyframes. I understand them as they relate to effects and animation in an edit context, and I use them all the time in my editing software.

The discussion we were having, as I perceived it, was about whether or not it's even possible to change keyframe parameters prior to the video capture process, as a setting on the camera. I've never seen anything written anywhere about that, nor have I ever seen or heard of a camera that has a setting for it. If you have information that would shed some light on that, it would be appreciated. As I understand it, the h.264 specification sets those parameters, and the end-user has no options in terms of adjusting keyframe frequency, or other similar adjustments.

All the above is totally separate and apart from using keyframes to control effects and animation parameters in the editing process, which are not part of this discussion.

 

[Geekhybrid]

You're right, I wasn't replying to the OP's post, but more to the essence of what you said: "In fact, the wiki on H.264/MPEG-4 AVC does not even include the word "keyframe"," which in itself was an OT reply in its examination of the H.264 codec.

I dunno, I kind of like that about forums. It's more like a discussion that is around a central idea, but strays into other ideas that touch it. Perhaps I am the only one in that fondness though.

 

[CriticalMass]

You're right, I wasn't replying to the OP's post, but more to the essence of what you said: "In fact, the wiki on H.264/MPEG-4 AVC does not even include the word "keyframe"," which in itself was an OT reply in its examination of the H.264 codec.

The whole discussion sort of took its own path since the OP was a no-show in most of it. We were forced to speculate on what he was really trying to do, since our questions went unanswered. Maybe the whole thing would have been best left alone.

But, I'm not sure I agree that my comment was off-topic in light of the ambiguities. Once some of us sort of agreed that the question was about whether or not keyframes in video encoding with h.264 could be controlled *before the fact*, that issue came front and center to become *THE TOPIC* of discussion. My reference to the wiki was relevant in that regard.

It was a strange discussion of the kind I'm not that fond of - too slippery, and no one really knows what to discuss. Oh, well - that's what can happen when people can't frame an intelligent question that has an intelligent answer.

 

[gcarter]

If you read the first 3 or 4 points on the "Features" Features section of that Wiki, they are all basically describing "key frames". That term is largely disparaged in descriptions of codecs, I have found. I guess it inaccurately describes what's happening and leads to confusion like this. Though it does often appear when you are on the user side of things, for example in a settings dialog box in Compressor or outputting from an Avid. It's just easier to understand, I guess.

The I, B and P frames you mention later just describe the frame type for inter or intra frame comparisons being made in the compression algorithm. But in short, as you've concluded, H.264 and variants ie. MPEG4) do use "key frames".


See key frames for explanation of some of the terms in the Features section mentioned above.

I also don't know if any of this answers the OPs questions. I haven't seen a frame inaccurate editing system since the early 90s SVHS editors. Even editing with Quicktime Player Pro from 10 years ago, I could still be frame accurate.

Edit: It does occur to me that one time "key frames" has come up is when editing H.264 footage in FCP. Basically, your edit point slip and come in at random points. It has something to do with the way H.264 encodes, tough I can't remember how, exactly. The solution is to trans-code all your H.264 footage to Apple ProRes, if that's the issue.

Quite a few MPG editors were very poor at doing frame accurate editing. Many of them that tried to do it (that said they could do it) often gave audio / video sync issues. Most consumer grade video editors / DVD authoring tools did a poor job.

 

[danvolker]

I shoot with a canon 5d mark II in Aquatica housing. What I assume you are looking for, is a way to get smoother video, when you have slow action suddenly becoming fast action, and then keeping up with the rapid scene changes. Please let me know if this is in fact, the "mission" you are on right now

If so, all we have is the max frame rate the camera will shoot at. I shoot at 30 frames per second, but there may be a way to shoot at 60 frames per second via firmware to camera....as in either 60 frames per second progressive, or 60 frames per second Interlaced ( which is similar to 30 progressive, but may be able to handle rapid scene changes better).

Another option, probably easier, would be getting your editing program to double or triple every frame in the discrete "video clips" where this is needed to achieve a smoother look--allowing slow motion effects to achieve much of what you were looking for....this is just spitballing, but it may help....