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• Capture raw video byte stream for real time transcoding

  9 septembre 2012, par user1145905

  I would like to achieve the following :

  Set up a proxy server to handle video requests by clients (for now, say all video requests from any Android video client) from a remote video server like YouTube, Vimeo, etc. I don't have access to the video files being requested, hence the need for a proxy server. I have settled for Squid. This proxy should process the video signal/stream being passed from the remote server before relaying it back to the requesting client.

  To achieve the above, I would either

  1. Need to figure out the precise location (URL) of the video resource being requested, download it really fast, and modify it as I want before HTTP streaming it back to the client as the transcoding continues (simultaneously, with some latency)

  2. Access the raw byte stream, pipe it into a transcoder (I'm thinking ffmpeg) and proceed with the streaming to client (also with some expected latency).

  Option #2 seems tricky to do but lends more flexibility to the kind of transcoding I would like to perform. I would have to actually handle raw data/packets, but I don't know if ffmpeg takes such input.

  In short, I'm looking for a solution to implement real-time transcoding of videos that I do not have direct access to from my proxy. Any suggestions on the tools or approaches I could use ? I have also read about Gstreamer (but could not tell if it's applicable to my situation), and MPlayer/MEncoder.

  And finally, a rather specific question : Are there any tools out there that, given a YouTube video URL, can download the byte stream for further processing ? That is, something similar to the Chrome YouTube downloader but one that can be integrated with a server-side script ?

  Thanks for any pointers/suggestions !

• What is the best way to write videos captured from webcam by OpenCV ?

  12 décembre 2013, par T.S.

  I have started using OpenCV with python recently and upon using this method to write a video file I was not content as 10 seconds of video were resulting in 1GB files.

  What is the recommended way to do it ? Use external tools like ffmpeg is something considered good practice for this type of thing ?

• ffmpeg capture streams in sync

  11 décembre 2013, par Mkoch

  I'd like to capture multiple real-time video streams arriving on rtp protocol, using ffmpeg. When I initiate the recording, by issuing the ffmpeg  <command line="line" parameters="parameters"></command> command, it always takes a while for the connection to built up and the actual recording to begin. This might be more than 2 seconds in certain cases, which cause a constant time difference at the replay.

  How can I extract the information containing the time of the first actually recorded frame from ffmpeg ? If it's not possible with ffmpeg without editing the source (which I did, and would like to avoid for other reasons), is there any similar multi-platform open-source tool which could be used ?