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• Revision 4d0ec7aacd : Consistently use get_prob(), clip_prob() and newly added clip_pixel(). Add a fu

  10 décembre 2012, par Ronald S. Bultje

  Changed Paths : Modify /vp9/common/vp9_common.h Modify /vp9/common/vp9_entropy.c Modify /vp9/common/vp9_entropymode.c Modify /vp9/common/vp9_entropymv.c Modify /vp9/common/vp9_filter.c Modify /vp9/common/vp9_idctllm.c Modify /vp9/common/vp9_pred_common.c (...)

• ffmpeg not converting an mp3 on OSX. Homebrew installed. Encoder (codec mp3) not found for output stream #0:0

  4 mai 2016, par Edward Potter

  Ok, did the standard hoembrew install for ffmpeg.

  All looks cool, i’m guessing that has to include the mpeg codec, yet I keep getting a 0 byte file and the error message :

  Encoder (codec mp3) not found for output stream #0:0

  Help most appreciated.

  ffmpeg -i input.mp3 -b:a 48k -ar 16000 output.mp3
  
  ffmpeg version 3.0.1 Copyright (c) 2000-2016 the FFmpeg developers
  
  built with Apple LLVM version 7.3.0 (clang-703.0.29)
  
  configuration:
  
  libavutil      55. 17.103 / 55. 17.103
  
  libavcodec     57. 24.102 / 57. 24.102
  
  libavformat    57. 25.100 / 57. 25.100
  
  libavdevice    57.  0.101 / 57.  0.101
  
  libavfilter     6. 31.100 /  6. 31.100
  
  libswscale      4.  0.100 /  4.  0.100
  
  libswresample   2.  0.101 /  2.  0.101
  
  [mp3 @ 0x7ff05a010600] Skipping 0 bytes of junk at 626.
  
  Input #0, mp3, from 'input.mp3':
  
  Metadata:
  
  title           : Allegro from Duet in C Major
  
  Duration: 00:00:59.56, start: 0.025057, bitrate: 192 kb/s
  
  Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
  
  Metadata:
  
    encoder         : LAME3.96r
  
  Output #0, mp3, to 'output.mp3':
  
  Metadata:
  
  title           : Allegro from Duet in C Major
  
  Stream #0:0: Audio: mp3, 0 channels, 128 kb/s
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (mp3 (native) -> ? (?))
  
  
  
  Encoder (codec mp3) not found for output stream #0:0

• Node.js asynchronous video conversion slow

  9 décembre 2016, par lukstei

  I wrote a little website/service, which can download a video from a website (currently Youtube) and converts it on the fly to an mp3 file and sends this file back as the response.

  For example, you when you request http://localhost:8000/v=http ://www.youtube.com/watch?v=HhoewflkQu0, then it will download this video and response the audio layer encoded in MP3.

  This all works very well, my problem is that this is very slow and I can’t figure out why.

  ---

  Simplified the script behaves like this :

  Download the video and write it to the stdin of ffmpeg, and the stdout goes to the response.
  Video (MP4, FLV) -> FFMPEG -> MP3

  I used curl to figure out how fast the script is :

  $ curl http://localhost:8000/v=http://www.youtube.com/watch?v=HhoewflkQu0

  I get only about 5-10k.

  So why is this so slow ?

  1. The server, from which I am downloading the video is slow.
  2. The conversion is slow (because of a slow CPU).
  3. The data transfer between node.js -> FFMPEG is slow.

  I tried to download the video in a normal download manager, and i got about 320k, which is my normal download speed, so the first point isn’t the bottleneck.

  To point 2 and 3, I tried to write a local file to the stdin, and I got about 600k so that isn’t it either.

  So why is my script so slow, and what can I do to make it faster ?

  https://gist.github.com/1304637

  Thanks in advance.