[FFmpeg-devel] [PATCH] ffmpeg/web/index: add news describing GSoC 2015 program outcome

[Stefano Sabatini]

On date Sunday 2015-09-27 09:44:33 -0400, Ganesh Ajjanagadde encoded:
> On Sun, Sep 27, 2015 at 8:37 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> > ---
> >  src/index | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 234 insertions(+)
[...]
> > +  <p>
> > +    During the program he extended the API with possibility to remove and
> > +    rename files on remote servers. He implemented/finished the
> > +    implementation of these features for file, Samba, SFTP, and FTP
> > +    protocols.
> > +  </p>
> 
> nit: with possiblity -> with the possibility
> 

> implemented/finished: is the vagueness necessary because some of these
> were completed and others not? Otherwise, I prefer the more explicit
> "implemented and finished".

Changed to: finished the implementation (since "implement the
implementations" sounds ugly/redundant).

> 
> > +
> > +  <p>
> > +    At the end of the program, Mariusz provided a sketch of implementation
> > +    for HTTP directory listening.
> > +  </p>
> > +
> > +  <h4>Directshow digital video capture, mentee: Mate Sebok, mentor: Roger Pack</h4>
> > +
> > +  <p>
> > +    Mate was working on directshow input from digital video sources. He
> > +    got working input from ATSC input sources, with specifiable tuner.
> > +  </p>
> > +
> > +  <p>
> > +    The code has not been committed, but a patch of it was sent to the
> > +    ffmpeg-devel mailing list for future use.
> > +  </p>
> > +
> > +  <p>
> > +    The mentor plans on cleaning it up and committing up, at least for the
> > +    ATSC side of things. Mate and the mentor are still working trying to
> > +    finally figure out how to get DVB working.
> > +  </p>
> 
> committing up - never heard this usage, perhaps "committing it" or
> even a simple "committing"?

=> committing it

[...]
> > +<h4>libswscale refactoring, mentee: Pedro Arthur, mentors: Michael Niedermayer, Ramiro Polla</h4>
> > +
> > +  <p>
> > +    Pedro Arthur has modlularized the vertical and horizontal scalers.
> > +    To do this he designed and implemented a generic filter framework
> > +    and moved the existing scaler code into it. These changes now allow
> > +    easily adding removing, splitting or merging processing steps.
> > +    The implementation was benchmarked and several alternatives where
> > +    tried to avoid speedloss.
> > +  </p>
> 
> modl.. -> modularized
> where tried -> were tried
> 
> > +
> > +  <p>
> > +    He also added gamma correct scaling support.
> > +    An example to use gamma corrected scaling would be:
> > +    <pre>
> > +      ffmpeg -i input -vf scale=512:384:gamma=1 output
> > +    </pre>
> > +  </p>
> 
> gamma correct scaling -> gamma corrected scaling
> 
> > +
> > +  <p>
> > +    Pedro has done impressive work considering the short time available,
> > +    and he is a FFmpeg comitter now. He continues to contribute to
> > +    FFmpeg, and has fixed some bugs in libswscale after GSoC has
> > +    ended.
> > +  </p>
> 
> comitter -> committer
> 
> > +
> > +  <h4>AAC Encoder Improvements, mentee: Rostislav Pehlivanov, mentor: Claudio Freire</h4>
> > +
> > +  <p>
> > +    Rostislav Pehlivanov has implemented PNS, TNS, I/S coding and main
> > +    prediction on the native AAC encoder. Of all those extensions, only
> > +    TNS was left in a less-than-usable state, but the implementation has
> > +    been pushed (disabled) anyway since it's a good basis for further
> > +    improvements.
> > +  </p>
> > +
> > +  <p>
> > +    PNS replaces noisy bands with a single scalefactor representing the
> > +    energy of that band, gaining in coding efficiency considerably, and
> > +    the quality improvements on low bitrates are impressive for such a
> > +    simple feature.
> > +  </p>
> > +
> > +  <p>
> > +    TNS still needs some polishing, but has the potential to reduce coding
> > +    artifacts by applying noise shaping in the temporal domain (something
> > +    that is a source of annoying, notable distortion on low-entropy
> > +    bands).
> > +  </p>
> > +
> > +  <p>
> > +    Intensity Stereo coding (I/S) can double coding efficiency by
> > +    exploiting strong correlation between stereo channels, most effective
> > +    on pop-style tracks that employ panned mixing. The technique is not as
> > +    effective on classic X-Y recordings though.
> > +  </p>
> > +
> > +  <p>
> > +    Finally, main prediction improves coding efficiency by exploiting
> > +    correlation among successive frames. While the gains have not been
> > +    huge at this point, Rostislav has remained active even after the GSoC,
> > +    and is polishing both TNS and main prediction, as well as looking for
> > +    furhter improvements to make.
> > +  </p>
> 
> furhter -> further
> 
> > +
> > +  <p>
> > +    In the process, the MIPS port of the encoder was broken a few times,
> > +    something he's also working to fix.
> > +  </p>
> > +
> > +  <h4>Animated Portable Network Graphics (APNG), mentee: Donny Yang, mentor: Paul B Mahol</h4>
> > +
> > +  <p>
> > +    Donny Yang implemented basic keyframe only APNG encoder as qualification
> > +    task, later he wrote kind of interframe compression via various blend
> > +    modes. Current implementation tries all blend modes and picks one which
> > +    takes the smallest amount of memory.
> > +  </p>
> 

> as qualification -> "as the qualification" or "as a qualification"
> depending on whether the qualification task is unique.

changed to: as the qualification

> change the , before later to a ; (or IMO a . with a fresh sentence)
> wrote kind of -> vague, ambiguous between "kind of wrote" and "wrote a
> type of". I think you wanted a "wrote a type of".

removed the "kind of" to the simpler "he wrote interframe compression
..."


> Current implementation -> The current implementation



> 
> > +
> > +  <p>
> > +    Special care was taken to make sure that the decoder plays correctly
> > +    all files found in wild and that the encoder produces files that can
> > +    be played in browsers that support APNG.
> > +  </p>
> 
> found in wild -> found in the wild
> 
> > +
> > +  <p>
> > +    During his work he was tasked to fix any encountered bug in the
> > +    decoder due to the fact that it doesn't match APNG
> > +    specifications. Thanks to this work, the also long standing bug in the
> > +    PNG decoder has been fixed.
> > +  </p>
> 
> Maybe reference the trac ticket number?

> the also long standing bug -> "a long standing bug" is simpler and
> conveys the same thing

opted for "a long standing bug .. has been fixed".


> > +

> > +  <p>
> > +    For latter work he plans to continue working on the encoder, making
> > +    possible to select which blend modes will be used in the encoding
> > +    process, which could speed up encoding of APNG files.
> > +  </p>
> 
> making possible -> making it possible

> remove the ,  add a . and say "This could speed up encoding of APNG files."

Yeah.

[...]

Thanks for the detailed review, updated version attached.
-- 
FFmpeg = Free and Fierce Multipurpose Patchable Eretic Governor
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