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• Using lcov With FFmpeg/Libav

  21 novembre 2011, par Multimedia Mike — Programming, code coverage, ffmpeg, lcov, libav

  Last year, I delved into code coverage tools and their usage with FFmpeg. I learned about using GNU gcov, which is powerful but pretty raw about the details it provides to you. I wrote a script to help interpret its output and later found another script called gcovr to do the same, only much better.

  I later found another tool called lcov which is absolutely amazing for understanding code coverage of your software. I’ve been meaning to use it to further FATE test coverage for the multimedia projects.

  
  
  Click for larger image
  

  Basic Instructions
  Install the lcov tool, of course. In Ubuntu, 'apt-get install lcov' will do the trick.

  Build the project with code coverage support, i.e.,

  ./configure —enable-gpl —samples=/path/to/fate/samples \
   —extra-cflags="-fprofile-arcs -ftest-coverage" \
   —extra-ldflags="-fprofile-arcs -ftest-coverage"
  make
  

  Clear the coverage data :

  lcov —directory . —zerocounters
  

  Run the software (in this case, the FATE test suite) :

  make fate
  

  Let lcov work its magic :

  lcov —directory . —capture —output-file coverage.info
  mkdir html-output
  genhtml -o html-output coverage.info
  

  At this point, you can aim your web browser at html-output/index.html to learn everything you could possibly want to know about code coverage of the test suite. You can sort various columns in order to see which modules have the least code coverage. You can drill into individual source files and see highlighted markup demonstrating which lines have been executed.

  As you can see from the screenshot above, FFmpeg / Libav are not anywhere close to full coverage. But lcov provides an exquisite roadmap.

• libavformat/matroska : Write stream durations in metadata, in the format of mkvmerge.

  5 août 2015, par Sasi Inguva

  libavformat/matroska : Write stream durations in metadata, in the format of mkvmerge.
  Compute individual stream durations in matroska muxer.
  
  Write them as string tags in the same format as mkvmerge tool does.
  Signed-off-by : Sasi Inguva <isasi@google.com>
  

  • [DH] libavformat/matroskaenc.c
  • [DH] tests/fate/wavpack.mak
  • [DH] tests/ref/acodec/tta
  • [DH] tests/ref/fate/binsub-mksenc
  • [DH] tests/ref/lavf/mkv
  • [DH] tests/ref/seek/lavf-mkv

• Read frames from a h264 video in java

  19 octobre 2014, par Shashank Tulsyan

  I am making a tool which records the user’s screen.
  It records almost every activity of the user and saves it as a h264 video.

  I also make a note of the window names.
  Then I make charts out of this data, which tells me how much time the user (me) has spend on what activity. Now I want to take this one level further.
  I want to be able to see the filtered video as well.

  Let’s say, I know I have spend 4 hrs on Netbeans, I also want to see a video showing what all I did on netbeans.

  Some sample video files

  http://neembuu.com/testdir/sat_1413633155981_direct.mkv
  http://neembuu.com/testdir/fri_1413547843213_direct.264

  I am using x264 for encoding.

  These files might be corrupt. Because encoding stops when the user shutsdown the pc or close the program. There is no handling of abrupt program exit. EOF is not written properly. This is a design decision.

  Now the problem is, none of the libraries ( jcodec , h264j ) seem to be able to decode these files.
  I want individual frames.

  Problem with h264j

  • Doesn’t support seeking
  • Randomly doesn’t work for some files, although all files have been created using the same settings ( like the sample fri_1413547843213_direct.264 , h264j doesn’t work with it. )

  Problem with jcodec.

  • Can’t handle mkv
  • Not sure how to use with raw h264 streams (<<< help would be appreciated here, so far I couldn’t find a way to handle raw h264 streams in jcodec )
  • If I used the jcodec’s MP4 muxer ( org.jcodec.samples.mux.AVCMP4Mux ) it does generate a mp4 but it is not able to read the same mp4 which it only generated
  • JCodec handles externally generated mp4 files pretty well. Can seek to any random frame and renders the frame BufferedImage beautifully, but it seems I don’t have my videos in a format which jcodec can handle.

  The encoding settings which I am using.

  x264 - --keyint 240 --sar 1:1 --output "destinationFile" --stitchable --fps 1/1 --input-res 1280x800 --input-csp rgb

  Any tip/advice. How can I make this work ?
  Thanks :D

  Ref : This question is in continuation of this How to make video from images using Java + x264 ; cross platform solution required