[FFmpeg-devel] Seeking api and gsoc

Michael Chinen mchinen
Mon Apr 5 00:49:07 CEST 2010


I may be interested in participating in GSoC 2010 with ffmpeg.  I hope this
is the right place to start talking.

I have noticed the seeking api project idea, and also that it seems to exist
from a previous year, unfinished.  I could not find info on what the state
is.  Is there some info page about this?

I would personally be interested in making sample-accurate seeking available
for audio.  I realize this is not exactly what the seeking api project is,
so I wanted to ask what would be acceptable in terms of a project.  Besides
the basic index-building implementation, I would also be interested in
implementing a functionality for building a 'probable' index as the file is
decoded, and an api that lets the client see how likely it is that the guess
will be valid.  For certain audio files, it may not be possible to quickly
build an index, but it may be possible to make guesses with increasing
certainty while the file is decoded from the start position, (for example,
one might say the file is seekable on a fixed size framerate by noticing the
frame size doesn't change after the first 10 seconds and we are at
approximately the right place in the file.)  These are my initial thoughts
about a GSoC project and I would like to hear how they sound to the ffmpeg
community.  My scope of personal interest is for audio, but if audio seeking
alone is not enough for a project, I would submit a project that also
handles video; however, I think focusing on audio may be ambitious enough
giving the amount of testing required for the various formats out there.

Another point - I develop on a mac - mostly using xcode.  I am somewhat
familliar with the configure/make style of building, but I wonder if it
would be of help if I added an xcode project to do this.  I have not yet
built ffmpeg on my machine, but will do soon if the reply from this email
suggests that I should apply to ffmpeg.  I found this for building
instructions on a mac, please let me know if there is another better one:

As a bit of background, I participated in GSoC 2008 though Audacity (the
same year in which LRN added ffmpeg support to audacity also through GSoC,)
adding on-demand (real-time background loading/seeking.) of wav files.  I
mentored for Audacity last year.  Audacity is not participating in it this
year, but I still want to use the opportunity to participate in a related
project.  Recently I added an experimental (not-enabled by default)
functionality that loads ffmpeg compatible files in the background while the
user can edit the decoded data.  I also want to add seeking support for
this, so the ffmpeg seeking api project looks promising and relevant to my
personal interests. I also do music/sound/hacking art using c/c++ on my
website which is not included (has a title that may trigger your spam
filter,) so these open-source audio projects are very interesting to me.

Michael Chinen

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