[FFmpeg-devel] [PATCH] Reduce default FDK decoder delay by one frame

Anshul anshul.ffmpeg at gmail.com
Fri Feb 28 15:52:31 CET 2014



Omer Osman <omer.osman at iis.fraunhofer.de> wrote:
>Dear members of FFmpeg-devel,
>
>
>First, I would like to apologize for the approach taken on the license 
>modification.
>
>
>I am working at Fraunhofer IIS department of Audio for Embedded
>Systems. 
>We are actively working on AAC technologies and are the developers of 
>the FDK library.
>The FDK library has been made publicly available through the Android 
>Open Source Project and became available for use outside of Android 
>through Martin Storsjö's github repository, and through his 
>implementation of libavcodec/libfdk-aac*.c wrapper.
>
>The FDK library itself is actively maintained by us in collaboration 
>with Google. As we are the developers of the FDK library, we see that 
>FFmpeg can benefit from our contributions, since we are aware of the 
>fine implementation details and can provide up-to-date and complete 
>wrapper patches as soon the FDK library is updated in the Android Open 
>Source Project and at github.
>
>As demonstrated by this patch, using the FDK decoder through FFmpeg 
>results in an additional output delay of one frame compared to FFmpeg 
>native AAC decoder. For file based decoding, the result of this is that
>
>the final output file is of the same size, but the last frame ends up 
>being "lost".

+1 i faced this.
>Additionally, we intend to provide an interface to features that are 
>currently not available in this wrapper. This includes Dynamic Range 
>Control metadata support, and LOAS decoding (which is currently 
>available through the FFmpeg native decoder but not through
>FFmpeg+FDK).
>
>What is intended by our first patch regarding the license is to provide
>
>a mechanism for us to be able to maintain this wrapper. We are aware 
>that the FFmpeg Development Policy states "Contributions should be 
>licensed under LGPL 2.1, including an 'or any later version' clause". 


>However, after consulting legal expertise, we have determined that it 
>would only be possible for us to contribute to FFmpeg under LGPL v2.1 
>only. The FDK library itself is under the 'FDK license' already, 
>requiring a build using '--enable-nonfree', and the wrapper is very 
>closely tied to the FDK library. Would it thus be possible to accept
>our 
>license change, limited only for this FDK wrapper, in order that we can
>
>contribute?

You said you determined. It would good if you share why and how u determine?
That would help us to determine. :)
>


>We realize that putting this requirement as part of the patch should 
>have been done separately from the patch itself, and for this we 
>apologize. Clearly, we do not intend to do this without the knowledge
>of 
>the original contributor of this wrapper, as he was put on cc in the 
>patch submission.
>
 I would also like to know that for how much time we should wait for.
When actual author does not reply.
Wait for some day, weeks or months.


>We wish now to ask how we can proceed.

It would be better idea to make different thread for what actual 
Implementation change u r trying
to do.
This thread has most of the disscussion on license issue.


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