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• ffplay seek when pts big than 26.5hour

  24 août 2016, par hansonzou

  I use ffmepg record rtsp stream to Ts file, but pts maxsize is 33bit(26.5hours,95443second).

  When I record more than 26.5 hours, pts will restart from 0. the ffplay can not seek more than 26.5 hours timestamp.

  How to change the ffplay to support it ?

  maybe i asked vaguely, the particulars is i save a rtsp stream to ts file by ffmpeg per 10 second , it may last for a long time(more than 26.5hour), when it done, it will save a m3u8 file, after that, i use ffplay to play then m3u8 file, if i want to seek to 26.7hour , the play must be stoped. -----PTS (sec) = 8589934592 / 90 000 Hz = 95443,7 seconds (26,5 hours)

• Extract specific frames of youtube video without downloading video

  22 janvier 2023, par Kashish Arora

  I need to extract specific frames of an online video to work on an algorithm but I don't want to download the whole video because that would make it highly inefficient.

  


  For starters, I tried working with youtube videos. I can download whole of the video using youtube-dl in this way :

  


  ydl_opts = {'outtmpl': r'OUTPUT_DIRECTORY_HERE',}
with youtube_dl.YoutubeDL(ydl_opts) as ydl:
    ydl.download([url])


  


  And then I can capture individual frames.

  


  I need to avoid downloading the whole video. After some research, I have found that ffmpeg might help me do this. I found no way to download just the frames so if this is not possible, the second option is that I can download specific portions of the video. One such example in linux is here but I couldn't find any solution for python.

  


  What is a good way to download just the frames, or portions of videos (in python) without downloading the entire thing ?

  


• Encoding FFMPEG to MPEG-DASH – or WebM with Keyframe Clusters – for MediaSource API

  6 août 2018, par Chris Nolet

  I’m currently sending a video stream to Chrome, to play via the MediaSource API.

  As I understand it, MediaSource only supports MP4 files encoded with MPEG-DASH, or WebM files that have clusters beginning with keyframes (otherwise it raises the error : Media segment did not begin with keyframe).

  Is there any way to encode in MPEG-DASH or keyframed WebM formats with FFMPEG in real-time ?

  Edit :

  I just tried it with ffmpeg ... -f webm -vcodec vp8 -g 1 so that every frame is a keyframe. Not the ideal solution. It does work with MediaStream now though. Any way to sync up the segments with the keyframes in WebM so not every frame needs to be a keyframe ?

  ---

  Reference Questions on WebM / MP4 and MediaSource :

  Media Source Api not working for a custom webm file (Chrome Version 23.0.1271.97 m)

  MediaSource API and mp4