Sur d’autres sites (12828)

• How to read a video stream(H.264) bitrate via ffprobe if the video is VBR

  26 janvier 2021, par Sean
  

  1. if the video stream is VBR, which means the bitrate is variable, so how to read the bitrate via ffprobe ?

  


  2. How to get know the video stream is CBR or VBR ?

  


  


• How to replace a snippet in a video without reencoding the whole video

  3 novembre 2022, par Simon Streicher

  I am trying to edit and replace a section of a video without reencoding the whole video.
Here are the steps I think I need to take :

  


  1. Find keyframes

  


  input :

  


  ffprobe -v error -select_streams v:0 -skip_frame nokey -show_entries frame=pkt_pts_time -of csv=p=0 'example.mkv'


  


  output :

  


  0.000000
1.001000
11.011000
13.430000
20.812000
30.822000
40.832000
50.842000
⋮


  


  2. Export relevant section

  


  For example, export the snippet 40.832000 → 50.842000.

  


  3. Edit and reencode

  


  After editing that section, I need to reencode it to the original codecs for compatibility with the surrounding video. For example, this is the original codecs :

  


  Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x1600 [SAR 1:1 DAR 12:5], 23.98 fps, 23.98 tbr, 1k tbn, 23.98 tbc (default)


  


  4. Inject edit back into the video stream

  


  Finally, I need to use FFmpeg somehow to retain everything from the original file (audio, subtitles, chapters, etc.) and to construct a new video stream (for example, Stream #0:0) that is exactly 0 → 40.832000 of the original, the whole edited section, and 50.842000 → end of the original section.

  


  My main questions are :

  


  

  • A. How do I trim the video stream in 2. without reencoding ?

  


  • B. Assuming that the edited video's resolution will remain the same, what is the command for FFmpeg to encode my edit to the codecs in 3. (and would the video be concatenable with the original video) ?

  


  • C. How should I go about glueing the sections together ? Should I simply trim Stream #0:0 into sections v1 = 0 → 40.832 and v2 = 50.842 → end and then concatenate a new stream as new = v1 + edited + v2 ?

  


  • D. How do I replace Stream #0:0 with new ?

  


  


  And probably the most important question : are my assumptions correct and can this be achieved ?

  


• voiceclient.play(discord.FFmpegPCMAudio) doesn't play any audio

  23 septembre 2021, par mm3239

  I'm trying to create a private music bot. It joined voice channel, but no sound came out and queue didn't worked. My play function is like this :

  


  async def play_music(self):
    if len(self.music_queue) > 0:
        self.is_playing = True

        index = self.music_queue[0][0]['index']

        #connecting to voice channel
        if not self.vc.is_connected():
            self.vc = await self.music_queue[0][1].connect()
        else:
            await self.vc.move_to(self.music_queue[0][1])

        self.music_queue.pop(0)

        self.vc.play(discord.FFmpegPCMAudio(self.music_files[index], **self.FFMPEG_OPTIONS), after=lambda e: self.play_next())


  


  When I execute the file, it should work like this :

  


  Me: /play abc.mp3
Bot: Song added to queue.
*abc song plays in voice channel*
Me: /play def.mp3
Bot: Song added to queue.
Me: /play ghi.mp3
Bot: Song added to queue.

Me: /queue
Bot: def.mp3
     ghi.mp3


  


  However, in reality, Discord :

  


  Me: /play abc.mp3
Bot: Song added to queue.
*silence*
Me: /play def.mp3
Bot: Song added to queue.
Me: /play ghi.mp3
Bot: Song added to queue.

Me: /queue
Bot: No music in queue.


  


  Console :

  


  music found!&#xA;[[{&#x27;index&#x27;: 2, &#x27;title&#x27;: &#x27;abc.mp3&#x27;}, <voicechannel>]]&#xA;music found!&#xA;[[{&#x27;index&#x27;: 0, &#x27;title&#x27;: &#x27;def.mp3&#x27;}, <voicechannel>]]&#xA;&#xA;music found!&#xA;[[{&#x27;index&#x27;: 1, &#x27;title&#x27;: &#x27;ghi.mp3&#x27;}, <voicechannel> position=5 bitrate=64000 user_limit=10 category_id=790202432072187909>]]&#xA;</voicechannel></voicechannel></voicechannel>

  


  I can see something's wrong(abc and def prints shorter message in console, middle part of message is skipped), but as you can see, it doesn't raise any error or exception. Could anyone please help me correct my code ? I'm completely stuck, and it would be really appreciated if someone could tell me what the problem is.