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• seeking mp4 with audiostream inaccurate in mobile safari

  23 février 2015, par dubbelj

  I have an issue with seeking an MP4 videofile on iOS (ipad). We use currentTime to skip through the video. This is working very well on most browsers, and also for h264 files without an audiostream on iOS. When I add an audiostream to the mp4 file however, the seeking becomes very inaccurate. This leads to all sorts of issues as the application bases a lot around timing.

  So we definitely concluded that a file that is encoded (using ffmpeg) with the exact same encoding settings but without audio is working well.

  These are the ffmpeg parameters I’m using when encoding with audio (added breaks for readability) :

  ffmpeg
  
  -i source.mov 
  
  -force_key_frames 00:00:04.840,00:00:04.880,00:00:04.920,00:00:04.960,00:00:05.000,00:00:05.040,00:00:05.080,00:00:14.760,00:00:14.800,00:00:14.840,00:00:14.880,00:00:14.920,00:00:14.960,00:00:15.000,00:00:24.760,00:00:24.800,00:00:24.840,00:00:24.880,00:00:24.920,00:00:24.960,00:00:25.000,00:00:31.720,00:00:31.760,00:00:31.800,00:00:31.840,00:00:31.880,00:00:31.920,00:00:31.960
  
  -c:a libvo_aacenc
  
  -b:a 128k 
  
  -ar 44100 
  
  -c:v libx264 
  
  -preset slow 
  
  -crf 21 
  
  -g 25 
  
  -r 25 
  
  -maxrate 2000k 
  
  -bufsize 2000k 
  
  -pix_fmt yuv420p 
  
  -movflags +faststart 
  
  -tune zerolatency 
  
  -vstats 
  
  encoded.mp4

  Things I’ve tried :

  • all available aac and mp3 codecs
  • different audio and video bitrates
  • different audio frequencies
  • with without zerolatency faststart flags
  • maximum amount of keyframes in file
  • settings keyframes only at (and around) the area where I need to skip to

  Any ideas anyone ?

• Combine video and audio with moviepy in mobile app

  18 novembre 2023, par GoodGameCrafter

  import moviepy.video.io.ffmpeg_tools as mvp
def Merge(self,title:str):  # Kombiniert die Video und die Audiodatei
    self.percent.text = "Verarbeiten..."
    os.rename(f"{self.outpath}/{title}.mp4", f"{self.outpath}/tmp_video.mp4")
    os.rename(f"{self.outpath}/{title}.mp3", f"{self.outpath}/tmp_video.mp3")
    mvp.ffmpeg_merge_video_audio( f"{self.outpath}/tmp_video.mp4",  f"{self.outpath}/tmp_video.mp3",
                                 f"{self.outpath}/{title}.mp4")
    os.remove(f"{self.outpath}/tmp_video.mp4")
    os.remove(f"{self.outpath}/tmp_video.mp3")


  


  I want to combine video and audio with moviepy in a kivy app on Android.I tried to build the app with the following requirements : python3,kivy,Pillow,typing_extensions,requests,urllib3,android,moviepy,imageio,Decorator,tqdm,numpy,imageio_ffmpeg,ffmpeg,proglog

  


  The app crashes and when i set the environmental variable with

  


  import os
os.environ["IMAGEIO_FFMPEG_EXE"] = "/usr/bin/ffmpeg"


  


  it does build the app but crashes when i try it out.
Is there something that I am missing or is it not possible to build this type of app ?

  


• Mobile Camera live audio/video streaming and encoding

  7 juin 2015, par Strikecounter2

  I know this question has been asked a couple of times, but I still haven’t found the right answer for my question.

  I would like to code an app that is able to live-stream audio and video while the content is being recorded and then uploaded to a server. I’d prefer to have my own back-end using Parse, because I want a high scalability. I know that the video has to be encoded to a h.264 codec and the audio to an AAC codec, but I don’t know how to achieve this. I have heard of the FFmpeg framework, but I am not sure if I would violate their license if I distribute my app or even sell it to somebody else.
  I would then like to receive the stream from the server to open it on the iPhone/android phone.

  They key requirements would be :

  • Low Latency
  • About 24 fps
  • Audio/Video in sync
  • No buffering while watching

  I would like to use Swift as a programming language, but if there is no way to use a swift-wrapper for any frameworks I would focus on Objective-C too.

  I am willing to learn everything that is needed, but I don’t know where to start.