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• How to build ffmpeg 0.11.1 on a Mac running Lion ?

  2 septembre 2012, par fabio

  I am aware that similar questions have been asked in the past, but things change continuously and I found some of the previous suggestions not to work (like the bambuser way, whose C compiler test failed.), be that because of the OS or because of older versions.

  So my question is, how can I build ffmpeg 0.11.1 using the Android NDK r8, on a Mac running Lion ? Any hint will be appreciated.

• Announcing x264 Summer of Code 2010 !

  19 mars 2010, par Dark Shikari — GSOC, development, google, x264

  With the announcement of Google Summer of Code 2010 and the acceptance of our umbrella organization, Videolan, we are proud to announce the third x264 Summer of Code ! After two years of progressively increasing success, we expect this year to be better than ever. Last year’s successes include ARM support and weighted P-frame prediction. This year we have a wide variety of projects of varying difficulty, including some old ones and a host of new tasks. The qualification tasks are tough, so if you want to get involved, the sooner the better !

  Interested in getting started ? Check out the wiki page, hop on #x264 on Freenode IRC, and say hi to the gang ! No prior experience or knowledge in video compression necessary : just dedication and the willingness to ask questions and experiment until you figure things out.

• Programmatically get non-overlapping images from MP4

  16 novembre 2019, par Carlos F

  My ultimate goal is to get meaningful snapshots from MP4 videos that are either 30 min or 1 hour long. "Meaningful" is a bit ambitious, so I have simplified my requirements.

  The image should be crisp - non-overlapping, and ideally not blurry. Initially, I thought getting a keyframe would work, but I had no idea that keyframes could have overlapping images embedded in them like this :

  Of course, some keyframe images look like this and those are much better :

  

  I was wondering if someone might have source code to :

  Take a sequence of say 10-15 continuous keyframes (jpg or png) and identify the best keyframe from all of them.

  This must happen entirely programmatically. I found this paper : http://research.microsoft.com/pubs/68802/blur_determination_compressed.pdf

  and felt that I could "rank" a few images based on the above paper, but then I was dissuaded by this link : Extracting DCT coefficients from encoded images and video given that my source video is an MP4. Of course, this confuses me because the input into the system is just a sequence of jpg images.

  Another link that is interesting is :

  Detection of Blur in Images/Video sequences

  However, I am not sure if this will work for "overlapping" images.