On date Sunday 2015-09-27 09:44:33 -0400, Ganesh Ajjanagadde encoded:
> On Sun, Sep 27, 2015 at 8:37 AM, Stefano Sabatini <stefa...@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
>From 1f8c1f79535993b5a7125921da767dc14a733a9e Mon Sep 17 00:00:00 2001
From: Stefano Sabatini <stefa...@gmail.com>
Date: Sun, 27 Sep 2015 14:36:16 +0200
Subject: [PATCH] ffmpeg/web/index: add news describing GSoC 2015 program
outcome
---
src/index | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 234 insertions(+)
diff --git a/src/index b/src/index
index 9d12a7b..bab319e 100644
--- a/src/index
+++ b/src/index
@@ -37,6 +37,240 @@
News
</h1>
+ <a id="gsoc2015_result"></a><h3>September 27th, 2015, GSoC 2015 results</h3>
+
+ <p>
+ FFmpeg participated to the latest edition of
+ the <a href="http://www.google-melange.com/gsoc/homepage/google/gsoc2015";>Google
+ Summer of Code</a> Project. FFmpeg got a total of 8 assigned
+ projects, and 7 of them were successful.
+ </p>
+
+ <p>We want to thank <a href="https://www.google.com";>Google</a>, the
+ participating students, and especially the mentors who joined this
+ effort. We're looking forward participating to the next GSoC
+ edition!
+ </p>
+
+ <p>
+ Below you can find a brief description of the final outcome of
+ each single project.
+ </p>
+
+ <h4>Basic servers for network protocols, mentee: Stephan Holljes, mentor: Nicolas George</h4>
+
+ <p>
+ Stephan Holljes's project for this session of Google Summer of Code was to
+ implement basic HTTP server features for libavformat, to complement the
+ already present HTTP client and RTMP and RTSP server code.
+ </p>
+
+ <p>
+ The first part of the project was to make the HTTP code capable of accepting
+ a single client; it was completed partly during the qualification period and
+ partly during the first week of the summer. Thanks to this work, it is now
+ possible to make a simple HTTP stream using the following commands:
+ <pre>
+ ffmpeg -i /dev/video0 -listen 1 -f matroska \
+ -c:v libx264 -preset fast -tune zerolatency http://:8080
+ ffplay http://localhost:8080/
+ </pre>
+ </p>
+
+ <p>
+ The next part of the project was to extend the code to be able to accept
+ several clients, simultaneously or consecutively. Since libavformat did not
+ have an API for that kind of task, it was necessary to design one. This part
+ was mostly completed before the midterm and applied shortly afterwards.
+ Since the ffmpeg command-line tool is not ready to serve several clients,
+ the test ground for that new API is an example program serving hard-coded
+ content.
+ </p>
+
+ <p>
+ The last and most ambitious part of the project was to update ffserver to
+ make use of the new API. It would prove that the API is usable to implement
+ real HTTP servers, and expose the points where more control was needed. By
+ the end of the summer, a first working patch series was undergoing code
+ review.
+ </p>
+
+ <h4>Browsing content on the server, mentee: Mariusz Szczepańczyk, mentor: Lukasz Marek</h4>
+
+ <p>
+ Mariusz finished an API prepared by the FFmpeg community and implemented
+ Samba directory listing as qualification task.
+ </p>
+
+ <p>
+ During the program he extended the API with the possibility to
+ remove and rename files on remote servers. He completed the
+ implementation of these features for file, Samba, SFTP, and FTP
+ protocols.
+ </p>
+
+ <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 it, 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>
+
+ <h4>Implementing full support for 3GPP Timed Text Subtitles, mentee: Niklesh Lalwani, mentors: Philip Langdale</h4>
+
+ <p>
+ Niklesh's project was to expand our support for 3GPP Timed Text
+ subtitles. This is the native subtitle format for mp4 containers, and
+ is interesting because it's usually the only subtitle format supported
+ by the stock playback applications on iOS and Android devices.
+ </p>
+
+ <p>
+ ffmpeg already had basic support for these subtitles which ignored all
+ formatting information - it just provided basic plain-text support.
+ </p>
+
+ <p>
+ Niklesh did work to add support on both the encode and decode side for
+ text formatting capabilities, such as font size/colour and effects like
+ bold/italics, highlighting, etc.
+ </p>
+
+ <p>
+ The main challenge here is that Timed Text handles formatting in a very
+ different way from most common subtitle formats. It uses a binary
+ encoding (based on mp4 boxes, naturally) and stores information
+ separately from the text itself. This requires additional work to track
+ which parts of the text formatting applies to, and explicitly dealing
+ with overlapping formatting (which other formats support) but Timed
+ Text does not - so it requires breaking the overlapping sections into
+ separate non-overlapping ones with different formatting.
+ </p>
+
+ <p>
+ Finally, Niklesh had to be careful about not trusting any size
+ information in the subtitles - and that's no joke: the now infamous
+ Android stagefright bug was in code for parsing Timed Text subtitles.
+ </p>
+
+ <p>
+ All of Niklesh's work is committed and was released in ffmpeg 2.8.
+ </p>
+
+<h4>libswscale refactoring, mentee: Pedro Arthur, mentors: Michael Niedermayer, Ramiro Polla</h4>
+
+ <p>
+ Pedro Arthur has modularized 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 were
+ tried to avoid speedloss.
+ </p>
+
+ <p>
+ He also added gamma corrected scaling support.
+ An example to use gamma corrected scaling would be:
+ <pre>
+ ffmpeg -i input -vf scale=512:384:gamma=1 output
+ </pre>
+ </p>
+
+ <p>
+ Pedro has done impressive work considering the short time available,
+ and he is a FFmpeg committer now. He continues to contribute to
+ FFmpeg, and has fixed some bugs in libswscale after GSoC has
+ ended.
+ </p>
+
+ <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
+ artefacts 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
+ further improvements to make.
+ </p>
+
+ <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 the
+ qualification task. Later he wrote interframe compression via
+ various blend modes. The current implementation tries all blend
+ modes and picks one which takes the smallest amount of memory.
+ </p>
+
+ <p>
+ Special care was taken to make sure that the decoder plays
+ correctly all files found in the wild and that the encoder
+ produces files that can be played in browsers that support APNG.
+ </p>
+
+ <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, a long standing bug in the
+ PNG decoder has been fixed.
+ </p>
+
+ <p>
+ For latter work he plans to continue working on the encoder,
+ making it possible to select which blend modes will be used in the
+ encoding process. This could speed up encoding of APNG files.
+ </p>
+
<a id="pr2.8"></a><h3>September 9th, 2015, FFmpeg 2.8</h3>
<p>
We published release <b><a href="download.html#release_2.8">2.8</a></b> as new major version.
--
1.9.1
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
