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• Is it possible to create new mp4 file from a single streaming byte range chunk ?

  22 avril 2014, par bevinlorenzo

  If I have a remote mp4 file on a server that supports Byte Ranges, is it possible to retrieve a single byte range and create a new/self-contained mp4 from that range data ?

  If I try and write a returned byte range data directly to an mp4 file using fs.createWriteStream(remoteFilename) it doesn’t get the video meta data (duration, dimensions, etc) that it needs to be playable.

  When I get a byte range that starts with 0 and ends with XX the output mp4 is playable, but will have the duration meta-data of the entire video length and will freeze the screen when the byte range is done for the remainder of the duration time.

  How else can I take a byte range and create a stand-alone .mp4 file from that stream object ?

  The whole point of this is to avoid downloading the entire 10 minute file before I can make a 5 second clip using ffmpeg. If I can calculate and download the byte range, there should be a way to write it to a standalone mp4 file.

  Thanks in advance for any help you can provide.

• ffmpeg cannot open a simple microsoft wav file exported with Audacity

  18 février 2014, par sebpiq

  I have exported a sound file to microsoft wav using Audacity.
  I am trying to open this file with ffmpeg :

  ffmpeg -i steps-stereo-16b-44khz.wav /tmp/test.ogg

  and here's the ouput I get :

  fmpeg version 1.2.1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 12 2013 13:46:11 with Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
  
    configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libschroedinger --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libspeex --enable-libass --enable-libbluray --enable-gnutls --enable-libfreetype --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  [dca @ 0x7fd30c013600] Not a valid DCA frame
  
  
  
  ... SNIP ...
  
  
  
  [dca @ 0x7fd5bc013600] Invalid bit allocation index
  
  [dca @ 0x7fd5bc013600] error decoding block
  
      Last message repeated 3 times
  
  [dca @ 0x7fd5bc013600] Didn't get subframe DSYNC
  
  [dca @ 0x7fd5bc013600] error decoding block
  
  [wav @ 0x7fd5bc013000] max_analyze_duration 5000000 reached at 5009070 microseconds
  
  [wav @ 0x7fd5bc013000] decoding for stream 0 failed
  
  [wav @ 0x7fd5bc013000] Could not find codec parameters for stream 0 (Audio: dts ([1][0][0][0] / 0x0001), 192000 Hz, 2 channels, fltp, 0 kb/s): no decodable DTS frames
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  steps-stereo-16b-44khz.wav: could not find codec parameters

  If I export the same file to .ogg or .aiff, no problem, the following works fine :

  ffmpeg -i steps-stereo-16b-44khz.aiff /tmp/test.ogg

  Any idea what could be wrong ?

  A link to my wav file so you can try to reproduce.

  NB my final goal is to slice the audio file. I know I can export file directly to .ogg with audacity. This is just a test case.

  EDIT

  Getting file info with another program like sox, works well :

  sox --info steps-stereo-16b-44khz.wav
  
  
  
  Input File     : 'steps-stereo-16b-44khz.wav'
  
  Channels       : 2
  
  Sample Rate    : 44100
  
  Precision      : 16-bit
  
  Duration       : 00:00:02.10 = 92608 samples = 157.497 CDDA sectors
  
  File Size      : 370k
  
  Bit Rate       : 1.41M
  
  Sample Encoding: 16-bit Signed Integer PCM

• Anomalie #3227 : Bug date de publication

  8 août 2014, par cedric -

  En fait je crois que la faute m’incombe.
  La date de redaction antérieure peut recevoir n’importe quel type de date. Par exemple pour indiquer la date d’origine d’un manuscrit du 15e siècle. Comme mysql ne le permet pas, on fake la date stockée en base pour supporter les dates anciennes.
  L’erreur a été de généraliser cela à la date de redaction/publication, qui elle doit toujours être valide, en effet !