Recherche avancée

Sur d’autres sites (4027)

• Piped FFMPEG won't write frames correctly

  12 novembre 2014, par user3180253

  I am using Python’s Image module to load JPEGs and modify them. After I have a modified image, I want to load that image in to a video, using more modified images as frames in my video.

  I have 3 programs written to do this :
  ImEdit (My image editing module that I wrote)
  VideoWriter (writes to an mp4 file using FFMPEG) and
  VideoMaker (The file I’m using to do everything)

  My VideoWriter looks like this...

  import subprocess as sp
  
  import os
  
  import Image
  
  FFMPEG_BIN = "ffmpeg"
  
  
  
  class VideoWriter():
  
     def __init__(self,xsize=480,ysize=360,FPS=29,
  
              outDir=None,outFile=None):
  
  
  
     if outDir is None:
  
        print("No specified output directory. Using default.")
  
        outDir = "./VideoOut"
  
     if outFile is None:
  
        print("No specified output file. Setting temporary.")
  
        outFile = "temp.mp4"
  
     if (outDir and outFile) is True:
  
        if os.path.exists(outDir+outFile):
  
           print("File path",outDir+outFile, "already exists:",
  
                 "change output filename or",
  
                 "overwriting will occur.")
  
     self.outDir = outDir
  
     self.outFile = outFile
  
     self.xsize,self.ysize,self.FPS = xsize,ysize,FPS
  
  
  
     self.buildWriter()
  
  
  
  def setOutFile(self,fileName):
  
     self.outFile = filename
  
  
  
  def setOutDir(self,dirName):
  
     self.outDir = dirName
  
  
  
  def buildWriter(self):
  
     commandWriter = [FFMPEG_BIN,
  
                      '-y',
  
                      '-f', 'rawvideo',
  
                      '-vcodec','mjpeg',
  
                      '-s', '480x360',#.format(480,
  
                      '-i', '-',
  
                      '-an', #No audio
  
                      '-r', str(29),
  
                      './{}//{}'.format(self.outDir,self.outFile)]
  
     self.pW = sp.Popen(commandWriter,
  
                        stdin = sp.PIPE)
  
  
  
  def writeFrame(self,ImEditObj):
  
     stringData = ImEditObj.getIm().tostring()
  
     im = Image.fromstring("RGB",(309,424),stringData)
  
     im.save(self.pW.stdin, "JPEG")
  
     self.pW.stdin.flush()
  
  
  
  def finish(self):
  
     self.pW.communicate()
  
     self.pW.stdin.close()

  ImEditObj.getIm() returns an instance of a Python Image object

  This code works to the extent that I can load one frame in to the video and no matter how many more calls to writeFrame that I do, the video only every ends up being one frame long. I have other code that works as far as making a video out of single frames and that code is nearly identical to this code. I don’t know what difference there is though that makes this code not work as intended where the other code does work.

  My question is...
  How can I modify my VideoWriter class so that I can pass in an instance of an Python’s Image object and write that frame to an output file ? I also would like to be able to write more than one frame to the video.

  I’ve spent 5 hours or more trying to debug this, having not found anything helpful on the internet, so if I missed any StackOverflow questions that would point me in the right direction, those would be appreciated...

  EDIT :
  After a bit more debugging, the issue may have been that I was trying to write to a file that already existed, however, this doesn’t make much sense with the -y flag in my commandWriter. the -y flag should overwrite any file that already exists. Any thoughts on that ?

• html5 video client side optimization

  3 décembre 2014, par Withfriendship Hiox

  I am using flowplayer and doing video quality selection as in the following page :

  Flowplayer quality selection

  User choose a quality and plays the video like 160p, 260p, 530p etc depending on their Internet speed to load the video quickly. However in the server side I have to encode the original video using Ffmpeg into each of these resolutions and store them.

  So it doing like video_1234_low.mp4, video_1234_mid.mp4, video_1234_high.mp4, etc. and switch the source to that video depending on which the user selects. This consumes a lot of drive space for large videos.

  Is there any possibility to load the video quickly without storing these files. Dynamic conversion on demand is difficult because it takes time. I wonder is there any client side trick to reduce the download size and play low quality video.

• ffmpeg rtmp and local file output

  19 mai 2016, par user3922282

  I’m new in stackoverflow =)
  I have a trouble with ffmpeg
  I receive a rtsp stream from a grabbing device (camera) and I stream-out it to rtmp (Youtube Live)
  I want to have a copy of the stream in my computer so I write at the same time in a local file

  I use this command :

  ffmpeg -y -i ’RTSP_SOURCE’ -c:v copy -c:a libvo_aacenc -map 0:v -bsf:v
  dump_extra -fflags +genpts -flags +global_header -movflags +faststart
  -map_metadata 0 -metadata title= -f tee -filter_complex aevalsrc=0 ’[f=mp4]/tmp/backup.mp4|[f=mpegts]/tmp/backup.ts|[f=flv]rtmp ://a.rtmp.youtube.com/live2/STREAM_ID’

  The problem is when I have some disconnections, ffmpeg exits and stop to recording
  Is there any flag or option for telling to ffmpeg to continue recording in local files even there is not internet ?

  Thank you very much for your help =)