ffmpeg impasse

Steven Robbins steve at sumost.ca
Sat Nov 5 19:29:26 GMT 2022


So thanks Maik and Gilles for the suggestion to look at Qt Multimedia.  If I 
can ask a dumb question to start: is there something blocking the use of qt 
multimedia?  It is present in Qt5 as well as Qt6.

On Thursday, October 27, 2022 12:55:17 A.M. CDT Gilles Caulier wrote:

> - As I understand in ffmpeg code (not easy to understand), the
> video/audio stream depends on codec and format processed which can
> give different results.

It's not clear to me what you mean by "different results".  If you are 
specifically referring to whether the video packet can produce more than one 
frame, then yes my understanding is that depends on the codec.  So things may 
"work" for certain files and not others.  

(Historically, my experience with digikam has been that quite a few of my 
videos don't play correctly -- I have no idea why, but now wondering whether 
it is related to this issue.)

> - I read somewhere in a forum (but I don't remember where, probably in
> QtAv area) that ffmpeg can be forced to be sync in stream processing
> (aka a decoding mode), but with degraded performances.

OK.  I am not aware of anything like that.

> Rewriting this class in QtAv can be a solution, after all QtAv author
> said that he will not maintain the code because it have not be well
> designed. I recommend first to take a look to the new ffmpeg interface
> implemented in Qt6::Multimedia as new module:
> https://code.qt.io/cgit/qt/qtmultimedia.git/tree/src/plugins/multimedia/ffmp
> eg
> We talked about it with Maik by private mails a few months ago, and it
> sounds like the future, if this module is stable and works better than
> QtAv. Also, it's only for Qt6 targets, not Qt5, 

You mean ffmpeg part of multimedia is missing from Qt5?  But there is /some/ 
video support in Qt5?  

(busy studying Qt multimedia ... )
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: This is a digitally signed message part.
URL: <http://mail.kde.org/pipermail/digikam-devel/attachments/20221105/58758ece/attachment.sig>

More information about the Digikam-devel mailing list