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• nodejs ffmpeg play video at specific time and stream it to client

  12 mars 2020, par bluejayke

  I’m trying to make a basic online video editor with nodeJS and ffmpeg.

  To do this I need 2 steps :

  1. set the in-and-out times of the videos from the client, which requires the client to view the video at specific times, and switch the position of the video. Meaning, if a single video is used as an input, and split it into smaller parts, it needs to replay from the starting time of the next edited segment, if that makes sense.

  2. send the input-output data to nodejs and export it with ffmpeg as a finished vide.

  At first I wanted to do 1. purely on the client, then upload the source video(s) to nodeJS, and generate the same result with ffmpeg, and send back the result.

  But there are may problems with video processing on the client side in HTML at the moment, so now I have a change of plans : to do all of the processing on the nodeJS server, including the video playing.

  This is the part I am stuck at now. I’m aware that ffmpeg can be used in many different ways from nodeJS, but I have not found a way to play a .mp4 webm video in realtime with ffmpeg, at a specific timestamp, and send the streaming video (again, at a certain timestamp) to the client.

  I’ve seen the pipe:1 attribute from ffmpeg, but I couldn’t find any tutorials to get it working with an mp4 webm video, and to parse the stdout data somehow with nodejs and send it to the client. And even if I could get that part to work, I still have no idea to play the video, in realtime, at a certain timestamp.

  I’ve also seen ffplay, but that’s only for testing as far as I know ; I haven’t seen any way of getting the video data from it in realtime with nodejs.

  So :

  how can I play a video, in nodeJS, at a specific time (preferably with ffmpeg), and send it back to the client in realtime ?

  What I have already seen :

  Best approach to real time http streaming to HTML5 video client

  Live streaming using FFMPEG to web audio api

  Ffmpeg - How to force MJPEG output of whole frames ?

  ffmpeg : Render webm from stdin using NodeJS

  No data written to stdin or stderr from ffmpeg

  node.js live streaming ffmpeg stdout to res

  Realtime video conversion using nodejs and ffmpeg

  Pipe output of ffmpeg using nodejs stdout

  can’t re-stream using FFMPEG to MP4 HTML5 video

  FFmpeg live streaming webm video to multiple http clients over Nodejs

  http://www.mobiuso.com/blog/2018/04/18/video-processing-with-node-ffmpeg-and-gearman/

  stream mp4 video with node fluent-ffmpeg

  How to get specific start & end time in ffmpeg by Node JS ?

  Live streaming : node-media-server + Dash.js configured for real-time low latency

  Low Latency (50ms) Video Streaming with NODE.JS and html5

  Server node.js for livestreaming

  HLS Streaming using node JS

  Stream part of the video to the client

  Video streaming with HTML 5 via node.js

  Streaming a video file to an html5 video player with Node.js so that the video controls continue to work ?

  How to (pseudo) stream H.264 video - in a cross browser and html5 way ?

  Pseudo Streaming an MP4 file

  How to stream video data to a video element ?

  How do I convert an h.264 stream to MP4 using ffmpeg and pipe the result to the client ?

  https://medium.com/@brianshaler/on-the-fly-video-rendering-with-node-js-and-ffmpeg-165590314f2

  node.js live streaming ffmpeg stdout to res

  Can Node.js edit video files ?

• avcodec/mpegpicture : Move caller-specific parts of function to callers

  3 octobre 2023, par Andreas Rheinhardt

  avcodec/mpegpicture : Move caller-specific parts of function to callers
  Since at least commit c954cf1e1b766a0d1992d5be0a8be0055a8e1a6a
  
  (adding ff_encode_alloc_frame()), a large part of ff_alloc_picture()
  
  is completely separate for the two callers. Move the caller-specific
  
  parts out to the callers.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/mpegpicture.c
  • [DH] libavcodec/mpegpicture.h
  • [DH] libavcodec/mpegvideo_dec.c
  • [DH] libavcodec/mpegvideo_enc.c

• FFMPEG - Download video in parts and concat, stutter at concat points

  23 juillet 2022, par rnbwSmn

  My goal is to download a video (or M3U8) in parts/chunks which I can later concat.

  


  For context, I would like to download videos in an Android Service which may be stopped at any time, so I think chunking is the right approach.

  


  After some time I got the "downloading the parts" right, using this. I would later put that in a function, and for now I chose the chunks to be 30 seconds long.

  


  %offset% = 30 * %part%

ffmpeg -ss %offset% -t 30 -i INPUT_FILE -avoid_negative_ts 1 out%part%.mp4


  


  The first line is just pseudocode, part is starting at 0.
This works fine, downloading 30 second long .mp4 files.

  


  After that I tried merging them together into a single .mp4. For the tests I only downloaded the first few parts.

  


  Concat command :

  


  ffmpeg -safe 0 -f concat -i concat.txt -c copy final.mp4


  


  This would be a very short concat.txt file :

  


  file 'out0.mp4'
file 'out1.mp4'


  


  The concat works but has one problem : At the point where both files are actually combined, so at 30 seconds, there is a small stutter in video and audio.

  


  So what I think is going on is that I download parts that are 30s long, starting at multiples of 30s so there is a small overlap ? In the "Details" part of the Windows file properties it also shows a length of 31 seconds, so the video is even longer than I want.

  


  I tried setting the duration of each part in the concat.txt, both to 30s and to 30s - 1 frame

  


  23.98 fps -> 1/23.98 spf = 0.0417s


  


  But with a duration of 30 as well as 29.9583, although it is better, there is still a small stutter.

  


  file 'out0.mp4'
duration 29.9583
file 'out1.mp4'
duration 29.9583


  


  I also tried with a different fileformat, .ts files, but the stutter was still there. I still think my timings are not quite right, but at this point I don't know where the problem is exactly. What do I need to change to remove the small stutter ?