QImage list to MP4

[ArsenArsen]

Hello! I have a program that saves a few QImages into memory and needs to convert them to a few formats. I am wondering how would I implement H264 wrapped in MP4 using eg. libavformat + libavcodec.

Has anyone tried this before and how hard should it be and should I keep using libavformat and libavcodec?
Thanks in advance,

[mrjj]

Hi
Using the libs directly is a bit more involved.
You need to understand/read the documentation and
it takes some effort to set up correctly.
Its much faster just calling ffmpeg via QProcess
https://trac.ffmpeg.org/wiki/Encode/H.264
https://en.wikibooks.org/wiki/FFMPEG_An_Intermediate_Guide/h.264
but if you must have in memory , there is no way. around it.
However, since ffmpeg uses libavformat and libavcodec it seems perfectly valid
to use them.

[ArsenArsen]

@mrjj, thanks for answering.
While it is not necessary for them to be in memory I would've preferred that. I can do anything to the images in my setup.

I wanted to do this first, but my issue was packing the binary with my application, for multiple reasons.
One of them is that I deploy for Windows, Linux and Mac. And One of my issues would be correctly obtaining the binary for the OS and architecture.
Second issue is choosing the format with the least waste and overhead which is going to be joined later.

I have been looking through examples but as I have little to no experience with media I basically have no clue what the examples are doing.
Thanks,

[mrjj]

@ArsenArsen
Well for the mentioned platform, there are installers available so it seem not huge
issue to bundle it. But I agree, there might be details with it.
https://ffmpeg.org/download.html

On the other hand, having the right libs for each platform and linking it will not be
super trivial either.

I would fool around with the samples
https://ffmpeg.org/doxygen/3.2/examples.html
and see how it felt before deciding which route would be best.

[ArsenArsen]

@mrjj
I'll try and report back here if I succeed (for further reference and other people which may experience the same issue)

[SGaist]

Hi and welcome to devnet,

IIRC H.264 is a licensed codec so you have to take that into account.

Otherwise, it's completely doable to use ffmpeg with Qt.

[ArsenArsen]

@SGaist said in QImage list to MP4:

H.264 is a licensed codec

Oh yep it is. Hrm. What should I do about that..

I guess contacting their licensing?

[SGaist]

AFAIK, yes, at least to know the conditions required to use the encoder.

Otherwise you have free formats like webm that you can use.

[ArsenArsen]

@SGaist I think I'll do that instead. I've been looking around and seems like getting licensed is a hellish process. I'll use WebM. Thanks for letting me know before I made the mistake :)

[ArsenArsen]

Turns out this is a lot easier than I first expected. Files are here. The link will soon be dead as I am merging that branch with master. Thanks for your support!

[VRonin]

@ArsenArsen said in QImage list to MP4:

Files are here.

goto

[ArsenArsen]

@VRonin Seems like the best choice there honestly, because the .... and this can be done without it. I see now.

Meh. It works.

inb4 dead

[J.Hilk]

@VRonin hey don't just goto to harshly, its still the best way to break out of nested loops...

...
Except mabye making the nested loop a function and using return....

[VRonin]

@J.Hilk said in QImage list to MP4:

its still the best way to break out of nested loops

bool breakAll=false;
for(int i=0;i<1000 && !breakAll;++i){
for(int j=0;j<1000 && !breakAll;++j){
if(shouldIStopEverything())
breakAll=true;
}
}

[ArsenArsen]

I wasn't wrong. The link is dead. New one

[VRonin]

We are going WAY off topic

bool Encoder::end() {
    if (success)
        av_write_trailer(fc);
    avcodec_free_context(&out->enc);
    av_frame_free(&out->frame);
    sws_freeContext(out->sws);
    delete out;
    if (!(fc->oformat->flags & AVFMT_NOFILE)) //
        avio_closep(&fc->pb);
    avformat_free_context(fc);
    return success;
}