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• Trimming and batch converting arbitrary video files to WebMs with python and ffmpeg

  22 juin 2018, par Romtromon

  I’ve got a whole lot of video files that I want to break up into multiple WebMs, each containing a trimmed portion of a specific video.

  I plan on having a csv file attached to each video file (having the same filename as the video) with a column structure similar to :

  Start Time | End Time | Rotation | Output Filename

  And I want to parse the csv files using python to execute ffmpeg, and I did a quick search and found the ffmpeg-python library and thought it might do the trick. The problem is, I don’t know the first thing about ffmpeg or video encoding. I’ve tried reading through the ffmpeg documentation and trying to replicate stuff using ffmpeg-python but the furthest I can get is an output video of the same format as the input file, trimmed (but mpv still shows the duration as the duration of the original file but cuts off playback when the end of the trim is reached) and without audio.

  As a side note, I currently use a software named "WebM for Retards" (excuse the offensive title) which uses ffmpeg and I’m happy with its output but it’s very tedious for my requirement. However I noticed that these are the arguments passed by using the software :

  -f nut -i pipe:0   -c:v libvpx -pix_fmt yuv420p -threads 8 -slices 4 -metadata title="This is a title" -ac 2 -c:a libvorbis -qmin 28 -crf 30 -qmax 32 -qcomp 1 -b:v 0 -qscale:a 3 -f webm -y "C:\Output.webm"

  I’d be happy if I could replicate output similar to what this provides. Thanks in advance for any help !

• Rendering a remote raw h264 video stream in javascript using WebRTC [on hold]

  20 mai 2018, par Shahabi

  I’m new in Video streaming and decoding for rendering on Web Browser.
  My plan is to create a raw h264 stream on localhost environment and in Nodejs application, I want to read the raw h264 stream and render it on Web browser with Low latency.

  For creating a stream, I’m using VLC Stream option in h264 format on HTTP server. I’m using my laptop webcam and mic for streaming audio/video on localhost environment.

  Now I’m stuck on getting that stream on web page and render it on Web browser.
  I want to use WebRTC or any other opensource library for fast rendering.

  Anyone know or guide me into the right direction where i can solve my problem as mention above ?

  Thanks

• Tile filter for libav/avconv

  26 avril 2018, par Mathjoh

  Is there some way to use libav/avconv to duplicate the effect of the tile filter in FFMPEG ?

  I’m trying to create a strip of images from left to right with one image for every ten seconds of video input.

  My plan is to first generate the images and then create the image strip. Preferably I want to use libav over ffmpeg. So far I have created this :

  avconv -i video.mp4 -vf scale=320:-1,fps=1/10 -q:v 6 img%03d.jpg

  which creates the images. But then I only know how create the image with ffmpeg using :

  ffmpeg -i img%03d.jpg -filter_complex tile=6x1 output.jpg

  So if anyone has any tips on how to rewrite the just the second or both commands to use avconv I welcome any advise :)