Recherche avancée

Sur d’autres sites (5577)

• Full HD video converted to FLV, slow playback in browser

  12 février 2012, par Boyan Georgiev

  I rendered a full HD video using Adobe AfterEffects CS5 in mp4 format. It plays just fine. I've got this video app to which I fed the mp4 file. The video app converts the mp4 to flv format and makes the video available via a web page. I've downloaded the resulting flv file to my local PC - it plays just fine in my VLC player. But, the problem is I'm getting awful playback inside my browser.

  I've made sure the issue is not bandwidth related.
  Both original mp4 file, and ffmpeg-converted FLV file, play perfectly using VLC player.
  I've tested the FLV file with two players - Agryia FLV Player Elite and JW Player. Both players play the video awfully - really slow and very choppy.

  Here's my ffmpeg -i myflvfile.flv :
  `

  Seems stream 0 codec frame rate differs from container frame rate: 119.88 (120000/1001) -> 59.92 (719/12)
  
  Input #0, flv, from '94044631305552037.flv':
  
  Metadata:
  
  duration        : 146
  
  width           : 1920
  
  height          : 1080
  
  videodatarate   : 684
  
  framerate       : 60
  
  videocodecid    : 7
  
  audiodatarate   : 62
  
  audiosamplerate : 22050
  
  audiosamplesize : 16
  
  stereo          : true
  
  audiocodecid    : 2
  
  major_brand     : mp42
  
  minor_version   : 0
  
  compatible_brands: mp42mp41
  
  creation_time   : 2012-02-10 00:55:19
  
  encoder         : Lavf52.111.0
  
  filesize        : 61969316
  
  Duration: 00:02:25.77, start: 0.034000, bitrate: 764 kb/s
  
  Stream #0.0: Video: h264 (High), yuv420p, 1920x1080 [PAR 3:4 DAR 4:3], 700 kb/s, 59.92 tbr, 1k tbn, 119.88 tbc
  
  Stream #0.1: Audio: mp3, 22050 Hz, stereo, s16, 64 kb/s`

  Can any one point me in the right direction here ? Why is playback perfect with VLC player of both the mp4 and the flv file on my local PC, yet in my browser, using two different players, the playback is so bad ?

  PS Here's my convert command :

  ffmpeg -y -i /var/www/sandverlag.com/htdocs/rmtk/videos/originals/94044631305552038.mp4 -vcodec libx264 -ar 22050 -ac 2 -vb 700000 -s 1920x1080 -crf 22 -threads 0 -f flv /var/www/sandverlag.com/htdocs/rmtk/videos/converted/94044631305552038.flv > /dev/null &    

• Joining h264 MP4 with ffmpeg Concat without re-encoding

  4 décembre 2013, par Lisa Jacobs

  I am trying to write a batch file to stitch 3 MP4 videos together without having to re-encode them, using a text file mylist.txt :

  file 'video1.mp4'
  
  file 'video2.mp4'
  
  file 'video3.mp4'

  I am stitching with : ffmpeg -f concat -i input.txt -c copy output.mp4 but for some reason the second video remains with a blackscreen and/or like if the stream was corrupted. It's like there was no keyframe at the beginning of video2.mp4 ? Video2.mp4 plays fine and does not seem to be corrupted.

• Extracting first frame in video using ffmpeg and android ndk

  12 mai 2014, par Papajohn000

  I’m trying to use android NDK and ffmpeg to extract the first frame of a video. I’ve seen a lot of examples on this website that use the command-line code that looks something like ffmpeg -i video.mp4 -vframes 1 -an -f image2 -y thumbmail.png 2>&1 I’m new to android NDK and I’m not sure how this plays into the native code file within the jni. Would it be used within a native method or is there a way to accomplish the same task another way using the ffmpeg libraries ?