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• 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

• Error in Splitting Educational Videos into Segments Using Python (ffmpeg issue) [closed]

  28 décembre 2024, par Yahia Mohamed Hanbal

  I created a Python project to split long educational videos into smaller segments, each focused on a single question. The program uses OCR to detect text on video frames, identifies the word "Question," extracts the number following it, and splits the video whenever the number increases.

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  here is the video i am tring to split ((video))

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  Here’s an example of the program’s output :

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  Video loaded: 14071 frames at 60 FPS, duration: 234.52s  
Frame 480, Time 8.00s, Question: 6  
...  
Frame 12360, Time 206.00s, Question: 7  
Creating segment 1: 8.00s to 206.00s  
Error: module 'ffmpeg' has no attribute 'Error'


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  I’ve shared the full code in a GitHub repository for reference : Automated Video Scene Cutting.

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  What the Program Does

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  • Input : A long educational video.

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  • Processing :&#xA;
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    • Detects text in each frame using OCR.

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    • Searches for the word "Question" followed by a number.

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    • Monitors when the number increases to identify segment boundaries.

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  • Output : Creates video segments corresponding to individual questions.

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  The Problem

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  The program detects the questions and timestamps correctly, but when it tries to create the segments, I encounter the following error :

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  Error: module 'ffmpeg' has no attribute 'Error'


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  What I’ve Tried

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  • Verified the ffmpeg-python library is installed (pip show ffmpeg-python confirms the installation).

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  • Ensured the ffmpeg binary is accessible from the command line.

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  • Reviewed the library documentation to ensure the correct usage of ffmpeg.

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  • Tested with different video files to rule out input-specific issues.

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  Environment Details

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  • OS : Windows 11

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  • Python Version : 3.9.13

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  • Key Libraries : ffmpeg-python

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  If anyone has insights into resolving this issue or suggestions for alternative approaches to handle this use case, I’d greatly appreciate your help.

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  Thank you !

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