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• Capturing two video sources into a single MKV with Java

  7 avril 2014, par Luke

  Problem

  I need my application to let the user record its screen, web cam and audio simultaneously. I have been able to accomplish this using a mix of Sarxos, Robot and Xuggler. But the various output files have different timing and are out of sync when played back synchronously.

  This is not hard to imagine given that the capturing is started asynchronously.

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  Possible solution

  I'm thinking that capturing the various sources into an MKV file with multiple video tracks might be a better solution. Some timer could poll the sources in parallel at regular intervals. Or at the very least blank audio/video-data could be inserted before any late capture start, to keep the video's and audio in sync.

  JMF would allow for very easy capturing, but doesn't seem to support MKV and is supposedly very outdated. I question whether it will work properly on current PCs and Macs. The FMJ Project might be an alternative, but MKV-support seems to be restricted to FFMPEG. This would defeat the purpose, as any kind of muxing or re-encoding afterwards would still leave the videos and audio out of sync. I could use Xuggler, as I do now, but it's impossible to find any relevant documentation or hints.

  Still, recording into a single file seems to make sense in order to get the timing straight.

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  My question

  Is anyone aware of a Java solution that would allow for encoding two video sources and an audio source into a single MKV container ?

• Android : Build a decoder library from Jpeg to MP4 video

  9 juillet 2014, par Ilya_Gazman

  I am working on Android 2.2, and my goal is to covert a sequence of images to mp4 video, MPEG-4_Part_14, to be more exact.

  The most reasonable solution would be using FFmpeg libraries, and compile them to Android using NDK. How ever I am looking for solution without NDK.

  I do not expect from you to build this tool for me, or find some one else who did. I spent quit of time now searching for that, and it’s some thing that probably no1 one did yet.

  So the only thing that I am asking, is help me find the specs so I be able to build the decoder by my self. I know that it’s not a trivial task(May be this is why no one did it yet), but I want to do it any way. So please just help me start it.

• Infinite stream with limited rewind length [duplicate]

  1er juin 2021, par Emanresu Siht

  The task is to have a cctv system where you only need the footage from now to x minutes in the past.
The easy solution is make images and deleting those older than x minutes.
The question now is is there a simple way to achieve this using a video live stream.

  


  Looking up the parameter options of ffmpeg only resulted in seeing the duration option that ends the recording after it reachs the given length, which is not the wanted result.
Other than this there is the segmentation option to split the video in parts. Like this it should be possible to delete the olders, but smoothly looking back x minutes into the past in a video player might be tricky if its split in two video parts ?

  


  Given there is a solution is it feasable to run on a raspberry pi as the recording, encoding and streaming device or is it needed to run the encoding and streaming on a more powerful machine ?