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• Preview video in android before saving to phone

  13 novembre 2014, par Zoe

  I’m in the process of creating a video editor for android.
  I am loading .mp4 videos into a timeline, where each rectangle in the timeline represents an imported video and I can drag/drop and rearrange these videos etc before saving the new .mp4 to my phone.

  I’ve been using mp4parser to do this, however I have ffmpeg loaded too but have avoided using this as I’m not too familiar with c++

  I have a space for a video player in my app. The idea is to have a seek line that can be dragged along the timeline as you are editing, and I want the player to be able to play a
  the edited video at the given point.

  However, the only examples on how to implement video players in android require you to load this video from your phone to play it. I was thinking I could just play the loaded videos separately but one after another giving the impression you’re watching a whole video, but I’m later planning to add functionality to include transitions and subtitles to videos which you would not be able to preview using this method.

  Any ideas on how about I can go about implementing a video player to preview the media whilst editing ?

  Thank you.

• ffmpeg for archval and convertability

  26 juillet 2021, par Satya

  I've got a couple hundred gigs of *.dv files. I'd like to convert them to H.264 or something else or even leave them alone. The purpose is archival, with an eye to maximum convertability especially to DVD. The content is family videos.

  


  Would this be fine ?

  


  ffmpeg -i input.dv \
    -c:v libx264 -preset slower \
    -crf 17 \
    -pix_fmt yuv420p \
    output.mp4


  


  I went with the slower preset because encoding time isn't an issue and I'd like a smaller file size. crf 17 is for least-lossy while being widely playable. I read somewhere that yuv420p is needed for some Quicktime players.

  


  Should I throw in -c:a aac for AAC audio ? The audio is voice only, no need for music-hall quality.

  


  I looked at https://trac.ffmpeg.org/wiki/Encode/H.264 for previous research and that's where I got those settings, but it is silent on the audio settings.

  


• WebRTC H264 video live streaming (w FFMPEG) from OpenGL

  25 novembre 2022, par OBI

  I am trying to make a peer-to-peer game streaming platform. At this point I managed to capture the OpenGL frames and I have a functional Java websockets server, I can have 2 clients that establish a peer to peer connection (I have solved the STUN/TURN servers part) and transfer text at this point.

  



  I do not quite understand how I could stream a video made out of the Opengl frames with a low latency (<100ms). The problem mainly lies in the FFMPEG part, I want to use this to encode the frames, get the result (stdin/stdout redirect for ffmpeg ?), somehow link to the the JS API of the host (maybe a local websocket to which the JS of the hoster will connect to).

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  I tried several FFMPEG arguements/commands with stdin and stdout pipes and they did not work.

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