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• Make MP4 video using JPEG 2000 frames and ROI

  21 mars 2012, par Leandro

  I'm having a hard time trying to figure out how to solve the following problem.

  I have a set of jp2 frames. I want to save them as a .mp4 video for archiving (which is great because it supports motion compensation) and then be able to extract the frames as jp2 files again.

  I have this working with a set of tools/libraries like ffmpeg. The issue is that I also want to include a ROI in the original jp2 images.

  When I do that, the video shows nothing where the ROI originally was, and when I use ffmpeg to go back to the original files, the frames are still broken.

  I tried going from JPEG2000 w\ ROI to another format before making the mp4 file, but every tool I use seems to have the same results : the ROI gets translated as a square w/o nothing there.

  Any help would be greatly appreciated.

  Thanks !

• Converting an RTP stream to RTSP or HTTP on Android

  15 mars 2012, par MobilityLab

  I have been trying to write and Android App for a specific application. Basically, I will have a device on the LAN that will be transmitting RTP packets containing H.264 encoded video, where all parameters are predefined. I need to capture these packets and display the video on an Android phone/tablet. My original thought was to capture all the RTP packets and add any additional packets that are necessary to supply the MediaPlayer class with enough information to display the video via RTSP.

  While I started to investigate that possibility, I found this, but the question remains unanswered.

  So, my question is, what advice/suggestions does anyone have for converting a RTP stream into a RTSP or HTTP context that MediaPlayer will understand. Does anyone know how to configure FFMPEG to do this ? Perhaps another tool that I can compile to Android, or a Java library that has this functionality.

  If you think I will have to manually code this process, any advice or references would be greatly appreciated.

  Thanks,

  Andrew @ MobilityLab

• ANSI Code Coverage Followup

  9 mars 2012, par Multimedia Mike — Programming

  The people behind sixteencolors.net noticed my code coverage project concerning the ANSI video decoder and asked what they could do to help. I had already downloaded 350 / 4000 of their artpacks but didn’t want to download the remainder if I could avoid it. They offered to run my tool against their local collection of files.

  Aside : They have all of the artpacks archived at Github.

  The full corpus of nearly 4000 artpacks contains over 146,000 files. Versus my sampling of 350 artpacks and 13,000 files that covered all but 45 lines of the ansi.c source file, the full corpus has files to exercise… 6 more of those lines. Whee. This means that there are files which exercise the reverse and concealed attributes, all 3 “erase in line” modes, and one more error path (which probably wasn’t a valid file anyway).

  Missing features mostly cluster around different video modes, including : 320×200 (25 rows), 640×200 (25 rows), 640×350 (43 rows), and 640×480 (60 rows) ; on the plus side, nothing tripped the “unsupported screen mode” case. There are no files that switch modes during playback.

  I guess statistical sampling theory holds out here– a small set of randomly chosen files would do a fine job covering code. But this experiment is about finding the statistical outliers.