Smart-Copy

[styrol]

If it is no longer possible in 2.6, how is one supposed to e.g. cut from the beginning a section which doesn't end on an I Frame?

You have to reencode. If you encode your source videos by yourself, you can determine the keyframe rate (e.g. every 12 Frames) in your encoder software.

Smart Copy works (worked only) on MPEG-4-Part-2-encoded files.

[UKenGB]

You have to reencode. If you encode your source videos by yourself, you can determine the keyframe rate (e.g. every 12 Frames) in your encoder software.

Smart Copy works (worked only) on MPEG-4-Part-2-encoded files.

Re-encoding is simply not an option. The whole point of using something like Avidemux is an ability to simply 'Copy' the existing audio and video, i.e. pass-thru what already has been encoded, degrading it further by re-encoding the whole thing. If you have to convert to a different encoder, then you have no choice, but it seems to me that many people (me included) want to keep the same encoded streams, but simply cut and trim them.

I can't see how setting a different keyframe rate can change anything. There will still be B and P Frames between the I Frames and there'll still be a problem when you want a cut in between I Frames.

Is there a universal SmartCopy actually in development?

[styrol]

but it seems to me that many people (me included) want to keep the same encoded streams, but simply cut and trim them.

So do I, but most questions in the forum are about converting (h.264 options) and using filters. So many users do other tasks using Avidemux. And I know a lot of users recording videos in HD and then compacting their stuff (re-encoding without visible quality lost).

Is there a universal SmartCopy actually in development?

I think you don't have much knowledge how frames are decoded and encoded in H.264. Smart-Copy is great, but I think it's hard to implement it. There are a few commercial programs doing Smart-Copy, if I remember correctly.

I can't see how setting a different keyframe rate can change anything.

Hypothetically, if you use "25 keyframes per second" at a frame rate of 25fps, then you get only I-Frames. If there are 3 keyframes per second, yes, you can only cut at I-Frames but you could cut indeed quite precisely.

[AQUAR]

Just a comment about the docs.
There are 2 versions of Avidemux with most of the docs being relevant to the 2.5 branch.

AVC provides a fantastic ratio of compression to quality but you pay the price with increased complexity.
Some of that cost is - difficult to cut/edit at any nilly willy virtual frame.
Avidemux 2.6 is working very nicely with AVC but it has to cut at real frames (as mentioned earlier).

[UKenGB]

I think you don't have much knowledge how frames are decoded and encoded in H.264.

And I think you're obviously not qualified to judge that. The fact I ask for an answer to a specific question doesn't mean I'm completely ignorant of the entire subject.

Smart-Copy is great, but I think it's hard to implement it.

I'm quite sure it is.

There are a few commercial programs doing Smart-Copy, if I remember correctly.

So not impossible then and hence not a stupid question to ask.

Also, as I'm not the OP, it's also clear that I'm not the only one who wants this feature. 

I can't see how setting a different keyframe rate can change anything.

Hypothetically, if you use "25 keyframes per second" at a frame rate of 25fps, then you get only I-Frames. If there are 3 keyframes per second, yes, you can only cut at I-Frames but you could cut indeed quite precisely.

Yes I had figured that out for myself, but presumably it's at the expense of file size so not the ideal solution, or not a solution at all depending on storage limitations.

[AQUAR]

@ UKenGB - People here were just trying to help you from a position based on the information You provided.
I am sure no offense was implied, but just the same, no-one here has a crystal ball that tells them what posters know or do not know.

I wish endusers would stop this audacity to demand changes without ever showing a smidgen of appreciation for this free and featurefull video editor. It certainly makes responding to issues less attractive and probably why so few bother at all.

Since you are not completely ignorant of the subject matter, why not read some related posts and improve your understanding as to how Avidemux 2.6 operates to get along with AVC.

AFAIK, from my limited enduser understanding,  Avidemux 2.6 relies on the AVC decoder for the complex frame reordering process needed to pop out the next frame in the video stream. Hence Avidemux cannot dictate the decoder to pop out a particular virtual frame as defined by DTS/PTS only the next frame (reference frames are okay!).

Only the developer can give you a more accurate appraisal of the why and how of current and future features and limitations.

[UKenGB]

Styrol has made it abundantly clear he has no desire to help and only makes disparaging (and incorrect) remarks about other's posts.

Look, I'm getting a bit fed up with this forum to be honest. I have already stated (here or in another thread) that I think Avidemux is great, but that doesn't mean it's perfect and when I see a thread someone else has started asking for a feature I think would be useful, it would be remiss of me if I didn't say, yes, I'd like that too. It's one thing to defend Avidemux by saying the feature would be hard to implement, but to proclaim I'm ignorant of the entire subject, just for saying I'd also like that feature is unacceptably rude, arrogant (and wrong).

Regarding the actual feature under discussion, I never demanded it, nor suggested it was easy to implement. Some other software seems to have managed to incorporate a Smartcopy and yes, I would really like it if Avidemux could too. While we're about it, I'd also like it to be able to add additional audio tracks based on an original track already in the file. Am I demanding either, no. Would I like to see them in Avidemux, yes. Does that make me a terrible person, apparently yes. Do I care, in truth, no.

If some forum members cannot accept someone else simply suggesting another feature they'd like to see included, then I would suggest they have no place on a forum such as this.

Me, I've lost interest in this forum and am unsubscribing from this thread. So go and beat up on someone else.

[zakk]

he has no desire to help and only makes disparaging (and incorrect) remarks about other's posts.

UkenGB, you have my full support and total agreement on this. I've used Avidemux and it's forum for years and some years ago, a few guys subscribed and start being rude to others, often with useless posts. You've already found one of them. I've already made remarks at two of them and got very violent reactions and little change of behaviour. The best thing is to try to ignore them, or delete your topic and restart another. But from now on I will start to make remarks again, since I don't want to loose new users just for 3 Avidemux worshipers who get mad if their favorite software gets a criticism.

[AQUAR]

@ Zakk are you including me in those 3?
If so I warn you,  stop defending endusers that inadvertently or otherwise incite negative reactions, especially when I am involved.
This kind of thing has NOTHING to do with Avidemux worship nonsense.

@ UKenGB
. Have a look at zakk's input before you fall for this false support.
. There is a broad spectrum in the way people interpret conversation. 
  Sometimes that crosstalk leads to unintended anger instead of goodwill from both parties.
. Styrol did try to help you and its not his fault you took that effort as useless or arrogant.
  Maybe try nurturing the conversation you initiated.
  Maybe avoid taking exception to some input provided by the only person that gave you time and effort.
  You could have kept the conversation pleasant by being the hero here.
. Of course You're perfectly fine in mentioning or supporting a video need that avidemux is lacking. That is very welcome here.
. If you leave in a huff and a puff then that is an unfortunate conclusion. Hopefully you do find what you need elsewhere.

Finally if everytime an enduser has to leave because of an incorrect remark this forum would only have one member.

[zakk]

Here' is another one.
(Now I'm unsubscribing from this topic, since I have nothing more to say and won't learn anything new.)

[Spellbinder]

Sorry guys, but I would like to go back to the topic:

So, what I understand is that my proposed solution could work, if it is possible to determine the videos encoder settings, BUT it would not be a quite "dirty" solution. So the question is if a developer would give it a try or if a developer is willing to try a "clean" solution. That would be GREATLY appriciated!

[AQUAR]

@ Spellbinder
Its an interesting topic for sure.
I wonder if there are various smartcopy concepts for AVC video that simply are not a practical fit for avidemux.
On AVC it would definitely be a great edit/cut feature.

Since avidemux is open source, anyone with the knowhow can generate smartcopy code for consideration.
In reality, Mean, the author of avidemux, is the only active developer wrt video processing code.
If there is going to be a smartcopy mode along the way you propose, Mean is the man to convince.

[Papou]

 

but it seems to me that many people (me included) want to keep the same encoded streams, but simply cut and trim them.

So do I, but most questions in the forum are about converting (h.264 options) and using filters. So many users do other tasks using Avidemux.
And I know a lot of users recording videos in HD and then compacting their stuff (re-encoding without visible quality lost).

The lack of discussions about AVC smart-copy is certainly not the reason why it's not implemented but a consequence.  The surprise is that the smart-copy that once was much thanked and applauded as a best pride of Avidemux has suddenly almost been called a sin just to fancy about.
No visible quality loss is no wonder if, said shortly, HD quality is better than the screen quality!
The problem comes with editing very different Youtube videos whose uploaders don't seem to realize that repeated reencoding loses much quality (MPEG -> FLV -> MP4 etc.) and seemingly also that they can be edited.

A typical case is Youtube Howto videos that, in principle, are understood by only 15% of the world (because of English) but in fact often 5% (because of the accent), of which you can't read the program menus because it's camera shot instead of desktop captured and during which the explanation can hold on for 20 seconds because the speaker has gone to fetch a pencil or something.  Did you speak of the dumb users of this forum?
If it were only me, I'd make the Howtos with screen captures if possible, I'd edit them with smart-copy and I'd put the speech in subtitles automatically translated in every languages by Google Translate to raise the audience from 5% to 85%.

And, if the big culprit is AVC, then I would simply use good old ASP because smart-copy is weighing more on the scale than the compression performance of AVC.

[AQUAR]

@ Papou
Your first sentence has multiple negation and can easily be mis-interpreted by some visitors here.
I point that out because that too is the kind of sin that you wish others would not commit.

Back to topic:

Avidemux 2.6 branch is a beta program that takes a different approach to its 2.5 branch cousin in getting at video frames.
The suprise/confusion is that most people continue to believe that 2.6 is an upgrade to 2.5.
These people automatically conclude that 2.6 has dropped much loved features, filters and configurability.
Smartcopy is one such feature where the 2.5 approach is not compatible with 2.6.
I don't agree with you at all in that talking about AVC smartcopy is frowned upon in this forum.

Slightly of topic:

The reality is that some people are easily transgressed when their perception is challenged in some way.
This kind of trend is scaring away people with the goodwill to respond, especially when rewarded with frustration and arrogance.
(And I betterer not mention those that delight in being a complicit factor.)
The heat when this topic arises has nothing to do with talking about smartcopy, its about people forgetting to be civil to each other.

Your perception of dumb users is also bit one sided IMHO. 
Its not so dumb when the Youtube videos are about presenting subject information, as opposed to best practise spatial resolution.
Of course it would be nicer to look at a good quality Youtube video (some are horrible!).

[Papou]

Suppose I split a video on I-frames into files 1, 2 and 3.
Then I edit file 2, split it on any frame and re-encode the end part into file 2a.
Then I append files 1, 2a and 3.
Haven't I done a smart copy?  Why would Avidemux 2.6 be unable to do that?
In principle, the only possible gotcha is selecting a compatible encoding.
But Avidemux should know.
Aren't all operations used here supposed to work?

Unfortunately, I tried that with a Youtube H.264 / AVC video.
I re-encoded part 2 with Codec Mpeg4 AVC (x264) standard options.
1, 2a and 3 play nicely on any renderer when standing alone, all 30 fps.
But after appending, part 2 shows a non moving picture or gray frame.

What's the trickery there?
NB: this (last) question is not a sinning suggestion to implement smart copy.
Just why a re-encoded part cannot be appended to its home video.