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• ffmpeg - Concat multi mp4 files with audio file not working

  29 mars 2017, par Thanh Dao

  I follow this thread to concat multi mp4 files with audio file.
  But its not success. Have a lots error notifications had been displayed. I dont know how to fix it.
  Below is my command :

  "ffmpeg" -f concat -safe 0 \
  
  -i /path/to/text.txt \
  
  -i /path/to/audio.mp3 -vsync vfr -vf scale="640:640" -pix_fmt yuv420p \
  
  /path/to/output.mp4 2>&1

  The detail contents of text.txt

  file '/path/to/file1.mp4'
  
  file '/path/to/file2.mp4'
  
  file '/path/to/file3.mp4'
  
  file '/path/to/file4.mp4'
  
  file '/path/to/file5.mp4'
  
  file '/path/to/file6.mp4'
  
  file '/path/to/file7.mp4'
  
  file '/path/to/file8.mp4'
  
  file '/path/to/file9.mp4'
  
  file '/path/to/file10.mp4'
  
  file '/path/to/file11.mp4'
  
  file '/path/to/file12.mp4'
  
  file '/path/to/file13.mp4'
  
  file '/path/to/file14.mp4'
  
  file '/path/to/file15.mp4'
  
  file '/path/to/file16.mp4'
  
  file '/path/to/file17.mp4'
  
  file '/path/to/file18.mp4'

  And some lines of output errors :

  [concat @ 0x357e620] DTS 192000 < 229888 out of order
  
  [h264 @ 0x36920e0] top block unavailable for requested intra mode -1
  
  [h264 @ 0x36920e0] error while decoding MB 32 0
  
  [h264 @ 0x36920e0] concealing 2025 DC, 2025 AC, 2025 MV errors in I frame
  
  [h264 @ 0x36b7a80] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36ff440] corrupted macroblock 26 1 (total_coeff=-1)
  
  [h264 @ 0x36ff440] error while decoding MB 26 1
  
  [h264 @ 0x36ff440] concealing 2003 DC, 2003 AC, 2003 MV errors in P frame
  
  [h264 @ 0x371af40] concealing 1456 DC, 1456 AC, 1456 MV errors in P frame
  
  [h264 @ 0x3736a40] ref 5 overflow
  
  [h264 @ 0x3736a40] error while decoding MB 1 1
  
  [h264 @ 0x3736a40] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3752520] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x376dfa0] P sub_mb_type 8 out of range at 2 1
  
  [h264 @ 0x376dfa0] error while decoding MB 2 1
  
  [h264 @ 0x376dfa0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x37a55a0] ref 6 overflow
  
  [h264 @ 0x37a55a0] error while decoding MB 3 1
  
  [h264 @ 0x37a55a0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3789aa0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36b7a80] ref 5 overflow
  
  [h264 @ 0x36b7a80] error while decoding MB 4 1
  
  [h264 @ 0x36b7a80] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x36920e0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame

• Server Move For multimedia.cx

  1er août 2014, par Multimedia Mike — General

  I made a big change to multimedia.cx last week : I moved hosting from a shared web hosting plan that I had been using for 10 years to a dedicated virtual private server (VPS). In short, I now have no one to blame but myself for any server problems I experience from here on out.

  The tipping point occurred a few months ago when my game music search engine kept breaking regardless of what technology I was using. First, I had an admittedly odd C-based CGI solution which broke due to mysterious binary compatibility issues, the sort that are bound to occur when trying to make a Linux binary run on heterogeneous distributions. The second solution was an SQLite-based solution. Like the first solution, this worked great until it didn’t work anymore. Something else mysteriously broke vis-à-vis PHP and SQLite on my server. I started investigating a MySQL-based full text search solution but couldn’t make it work, and decided that I shouldn’t have to either.

  Ironically, just before I finished this entire move operation, I noticed that my SQLite-based FTS solution was working again on the old shared host. I’m not sure when that problem went away. No matter, I had already thrown the switch.

  How Hard Could It Be ?
  We all have thresholds for the type of chores we’re willing to put up with and which we’d rather pay someone else to perform. For the past 10 years, I felt that administering a website’s underlying software is something that I would rather pay someone else to worry about. To be fair, 10 years ago, I don’t think VPSs were a thing, or at least a viable thing in the consumer space, and I wouldn’t have been competent enough to properly administer one. Though I would have been a full-time Linux user for 5 years at that point, I was still the type to build all of my own packages from source (I may have still been running Linux From Scratch 10 years ago) which might not be the most tractable solution for server stability.

  These days, VPSs are a much more affordable option (easily competitive with shared web hosting). I also realized I know exactly how to install and configure all the software that runs the main components of the various multimedia.cx sites, having done it on local setups just to ensure that my automated backups would actually be useful in the event of catastrophe.

  All I needed was the will to do it.

  The Switchover Process
  Here’s the rough plan :

  • Investigate options for both VPS providers and mail hosts– I might be willing to run a web server but NOT a mail server
  • Start plotting several months in advance of my yearly shared hosting renewal date
  • Screw around for several months, playing video games and generally finding reasons to put off the move
  • Panic when realizing there are only a few days left before the yearly renewal comes due

  So that’s the planning phase. BTW, I chose Digital Ocean for VPS and Zoho for email hosting. Here’s the execution phase I did last week :

  • Register with Digital Ocean and set up DNS entries to point to the old shared host for the time being
  • Once the D-O DNS servers respond correctly using a manual ‘dig’ command, use their servers as the authoritative ones for multimedia.cx
  • Create a new Droplet (D-O VPS), install all the right software, move the databases, upload the files ; and exhaustively document each step, gotcha, and pitfall ; treat a VPS as necessarily disposable and have an eye towards iterating the process with a new VPS
  • Use /etc/hosts on a local machine to point DNS to the new server and verify that each site is working correctly
  • After everything looks all right, update the DNS records to point to the new server

  Finally, flip the switch on the MX record by pointing it to the new email provider.

  Improvements and Problems
  Hosting on Digital Ocean is quite amazing so far. Maybe it’s the SSDs. Whatever it is, all the sites are performing far better than on the old shared web host. People who edit the MultimediaWiki report that changes get saved in less than the 10 or so seconds required on the old server.

  Again, all problems are now my problems. A sore spot with the shared web host was general poor performance. The hosting company would sometimes complain that my sites were using too much CPU. I would have loved to try to optimize things. However, the cPanel interface found on many shared hosts don’t give you a great deal of data for debugging performance problems. However, same sites, same software, same load on the VPS is considerably more performant.

  Problem : I’ve already had the MySQL database die due to a spike in usage. I had to manually restart it. I was considering a cron-based solution to check if the server is running and restart it if not. In response to my analysis that my databases are mostly read and not often modified, so db crashes shouldn’t be too disastrous, a friend helpfully reminded me that, “You would not make a good sysadmin with attitudes like ‘an occasional crash is okay’.”

  To this end, I am planning to migrate the database server to a separate VPS. This is a strategy that even Digital Ocean recommends. I’m hoping that the MySQL server isn’t subject to such memory spikes, but I’ll continue to monitor it after I set it up.

  Overall, the server continues to get modest amounts of traffic. I predict it will remain that way unless Dark Shikari resurrects the x264dev blog. The biggest spike that multimedia.cx ever saw was when Steve Jobs linked to this WebM post.

  Dropped Sites
  There are a bunch of subdomains I dropped because I hadn’t done anything with them for years and I doubt anyone will notice they’re gone. One notable section that I decided to drop is the samples.mplayerhq.hu archive. It will live on, but it will be hosted by samples.ffmpeg.org, which had a full mirror anyway. The lower-end VPS instances don’t have the 53 GB necessary.

  Going Forward
  Here’s to another 10 years of multimedia.cx, even if multimedia isn’t as exciting as it was 10 years ago (personal opinion ; I’ll have another post on this later). But at least I can get working on some other projects now that this is done. For the past 4 months or so, whenever I think of doing some other project, I always remembered that this server move took priority over everything else.

• Reading in pydub AudioSegment from url. BytesIO returning "OSError [Errno 2] No such file or directory" on heroku only ; fine on localhost

  24 octobre 2014, par Mark

  EDIT 1 for anyone with the same error : installing ffmpeg did indeed solve that BytesIO error

  EDIT 1 for anyone still willing to help : my problem is now that when I AudioSegment.export("filename.mp3", format="mp3"), the file is made, but has size 0 bytes — details below (as "EDIT 1")

  ---

  EDIT 2 : All problems now solved.

  • Files can be read in as AudioSegment using BytesIO
  • I found buildpacks to ensure ffmpeg was installed correctly on my app, with lame support for exporting proper mp3 files

  Answer below

  ---

  Original question

  I have pydub working nicely locally to crop a particular mp3 file based on parameters in the url.
  (?start_time=3.8&end_time=5.1)

  When I run foreman start it all looks good on localhost. The html renders nicely.
  The key lines from the views.py include reading in a file from a url using

  url = "https://s3.amazonaws.com/shareducate02/The_giving_tree__by_Alex_Blumberg__sponsored_by_mailchimp-short.mp3"
  
  mp3 = urllib.urlopen(url).read() # inspired by http://nbviewer.ipython.org/github/ipython-books/cookbook-code/blob/master/notebooks/chapter11_image/06_speech.ipynb
  
  original=AudioSegment.from_mp3(BytesIO(mp3))  # AudioSegment.from_mp3 is a pydub command, see http://pydub.com
  
  section = original[start_time_ms:end_time_ms]

  That all works great... until I push to heroku (django app) and run it online.
  then when I load the same page now on the herokuapp.com, I get this error

  OSError at /path/to/page
  
  [Errno 2] No such file or directory
  
  Request Method: GET
  
  Request URL:    http://my.website.com/path/to/page?start_time=3.8&end_time=5
  
  Django Version: 1.6.5
  
  Exception Type: OSError
  
  Exception Value:    
  
  [Errno 2] No such file or directory
  
  Exception Location: /app/.heroku/python/lib/python2.7/subprocess.py in _execute_child, line 1327
  
  Python Executable:  /app/.heroku/python/bin/python
  
  Python Version: 2.7.8
  
  Python Path:    
  
  ['/app',
  
   '/app/.heroku/python/bin',
  
   '/app/.heroku/python/lib/python2.7/site-packages/setuptools-5.4.1-py2.7.egg',
  
   '/app/.heroku/python/lib/python2.7/site-packages/distribute-0.6.36-py2.7.egg',
  
   '/app/.heroku/python/lib/python2.7/site-packages/pip-1.3.1-py2.7.egg',
  
   '/app',
  
   '/app/.heroku/python/lib/python27.zip',
  
   '/app/.heroku/python/lib/python2.7',
  
   '/app/.heroku/python/lib/python2.7/plat-linux2',
  
   '/app/.heroku/python/lib/python2.7/lib-tk',
  
   '/app/.heroku/python/lib/python2.7/lib-old',
  
   '/app/.heroku/python/lib/python2.7/lib-dynload',
  
   '/app/.heroku/python/lib/python2.7/site-packages',
  
   '/app/.heroku/python/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg-info']
  
  
  
  
  
  Traceback:
  
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  
    112.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
  
  File "/app/evernote/views.py" in finalize
  
    105.       original=AudioSegment.from_mp3(BytesIO(mp3))
  
  File "/app/.heroku/python/lib/python2.7/site-packages/pydub/audio_segment.py" in from_mp3
  
    318.         return cls.from_file(file, 'mp3')
  
  File "/app/.heroku/python/lib/python2.7/site-packages/pydub/audio_segment.py" in from_file
  
    302.         retcode = subprocess.call(convertion_command, stderr=open(os.devnull))
  
  File "/app/.heroku/python/lib/python2.7/subprocess.py" in call
  
    522.     return Popen(*popenargs, **kwargs).wait()
  
  File "/app/.heroku/python/lib/python2.7/subprocess.py" in __init__
  
    710.                                 errread, errwrite)
  
  File "/app/.heroku/python/lib/python2.7/subprocess.py" in _execute_child
  
    1327.                 raise child_exception

  I have commented out some of the original to convince myself that sure enough the single line original=AudioSegment.from_mp3(BytesIO(mp3)) is where the problem kicks in... but this is not a problem locally

  The full function in views.py starts like this :

  from django.shortcuts import render, get_object_or_404 
  
  from django.http import HttpResponseRedirect #, Http404, HttpResponse
  
  from django.core.urlresolvers import reverse
  
  from django.views import generic
  
  import pydub
  
  # Maybe only need: 
  
  from pydub import AudioSegment # == see below
  
  from time import gmtime, strftime
  
  
  
  import boto
  
  from boto.s3.connection import S3Connection
  
  from boto.s3.key import Key
  
  
  
  # http://nbviewer.ipython.org/github/ipython-books/cookbook-code/blob/master/notebooks/chapter11_image/06_speech.ipynb
  
  import urllib
  
  from io import BytesIO
  
  # import numpy as np
  
  # import scipy.signal as sg
  
  # import pydub # mentioned above already
  
  # import matplotlib.pyplot as plt
  
  # from IPython.display import Audio, display
  
  # import matplotlib as mpl
  
  # %matplotlib inline
  
  
  
  import os
  
  # from settings import AWS_ACCESS_KEY, AWS_SECRET_KEY, AWS_BUCKET_NAME
  
  AWS_ACCESS_KEY = os.environ.get('AWS_ACCESS_KEY') # there must be a better way?
  
  AWS_SECRET_KEY = os.environ.get('AWS_SECRET_KEY')
  
  AWS_BUCKET_NAME = os.environ.get('S3_BUCKET_NAME')
  
  
  
  # http://stackoverflow.com/questions/415511/how-to-get-current-time-in-python
  
  
  
  boto_conn = S3Connection(AWS_ACCESS_KEY, AWS_SECRET_KEY)
  
  bucket = boto_conn.get_bucket(AWS_BUCKET_NAME)
  
  s3_url_format = 'https://s3.amazonaws.com/shareducate02/{end_path}'

  and specifically the view in views.py that’s called when I visit the page :

  def finalize(request):
  
  
  
      start_time = request.GET.get('start_time')
  
  
  
      end_time = request.GET.get('end_time')
  
  
  
      original_file = "https://s3.amazonaws.com/shareducate02/The_giving_tree__by_Alex_Blumberg__sponsored_by_mailchimp-short.mp3"
  
  
  
  
  
      if start_time:
  
  
  
        # original=AudioSegment.from_mp3(original_file)  #...that didn't work 
  
        # but this works below:
  
  
  
        # next three uncommented lines from http://nbviewer.ipython.org/github/ipython-books/cookbook-code/blob/master/notebooks/chapter11_image/06_speech.ipynb
  
        # python 2.x
  
        url = original_file
  
        # req = urllib.Request(url, headers={'User-Agent': ''}) # Note: I commented out this because I got error that "Request" did not exist
  
        mp3 = urllib.urlopen(url).read()
  
        # That's for my 2.7
  
  
  
        # If I ever upgrade to python 3.x, would need to change it to:
  
        # req = urllib.request.Request(url, headers={'User-Agent': ''}) 
  
        # mp3 = urllib.request.urlopen(req).read()
  
        # as per instructions on http://nbviewer.ipython.org/github/ipython-books/cookbook-code/blob/master/notebooks/chapter11_image/06_speech.ipynb
  
  
  
        original=AudioSegment.from_mp3(BytesIO(mp3))
  
        # original=AudioSegment.from_mp3("static/givingtree.mp3") # alternative that works locally (on laptop) but no use for heroku
  
  
  
        start_time_ms = int(float(start_time) * 1000)
  
        if end_time:
  
          end_time_ms = int(float(end_time) * 1000)
  
        else:
  
          end_time_ms = int(float(original.duration_seconds) * 1000)
  
        duration_ms = end_time_ms - start_time_ms
  
        # duration = end_time - start_time
  
        duration = duration_ms/1000
  
  
  
     #   section = original[start_time_ms:end_time_ms]
  
     #   section_with_fading = section.fade_in(100).fade_out(100)
  
  
  
        clip = "demo-"
  
        number = strftime("%Y-%m-%d_%H-%M-%S", gmtime())
  
        clip += number
  
        clip += ".mp3" 
  
  
  
        # DON'T BOTHER writing locally:
  
        # clip_with_path = "evernote/static/"+clip
  
        # section_with_fading.export(clip_with_path, format = "mp3")
  
  
  
     #   tempclip = section_with_fading.export(format = "mp3")
  
  
  
        # commented out while de-bugging, but was working earlier if run on localhost
  
        # c = boto.connect_s3()
  
        # b = c.get_bucket(S3_BUCKET_NAME)  # as defined above
  
        # k = Key(b)
  
        # k.key=clip
  
        # # k.set_contents_from_filename(clip_with_path)
  
        # k.set_contents_from_file(tempclip)
  
        # k.set_acl('public-read')
  
        clip_made = True
  
      else: 
  
        duration = 0.0
  
        clip_made = False
  
        clip = ""
  
      context = {'original_file':original_file, 'new_file':clip, 'start_time': start_time, 'end_time':end_time, 'duration':duration, 'clip_made':clip_made} 
  
      return render(request, 'finalize.html' , context) 

  Any suggestions ?

  Potentially related :
  I have ffmpeg installed locally

  But have been unable to install it onto heroku, due to not understanding buildpacks. I tried just a moment ago (http://stackoverflow.com/questions/14407388/how-to-install-ffmpeg-for-a-django-app-on-heroku and https://github.com/shunjikonishi/heroku-buildpack-ffmpeg) but so far ffmpeg is not working on heroku (ffmpeg is not recognised when I do "heroku run ffmpeg —version")
  ...do you think this is the reason ?

  An answer like any of these would be much appreciated as I’m going round in circles here :

  1. "I think ffmpeg is indeed your problem. Try harder to sort that out, to get it installed on heroku"
  2. "Actually, I think this is why BytesIO is not working for you : ..."
  3. "Your approach is terrible anyway... if you want to read in an audio file to process using pydub, you should just do this instead : ..." (since I’m just hacking my way through pydub for my first time... my approach may be poor)

  ---

  EDIT 1

  ffmpeg is now installed (e.g., I can output wav files)

  However, I can’t create mp3 files, still... or more correctly, I can, but the filesize is zero

  (venv-app)moriartymacbookair13:getstartapp macuser$ heroku config:add BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi.git 
  
  Setting config vars and restarting awe01... done, v93
  
  BUILDPACK_URL: https://github.com/ddollar/heroku-buildpack-multi.git
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ vim .buildpacks 
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ cat .buildpacks 
  
  https://github.com/shunjikonishi/heroku-buildpack-ffmpeg.git
  
  https://github.com/heroku/heroku-buildpack-python.git
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ git add --all
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ git commit -m "need multi, not just ffmpeg, so adding back in multi + shun + heroku, with trailing .git in .buildpacks file"
  
  [master cd99fef] need multi, not just ffmpeg, so adding back in multi + shun + heroku, with trailing .git in .buildpacks file
  
   1 file changed, 2 insertions(+), 2 deletions(-)
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ git push heroku master
  
  Fetching repository, done.
  
  Counting objects: 5, done.
  
  Delta compression using up to 4 threads.
  
  Compressing objects: 100% (3/3), done.
  
  Writing objects: 100% (3/3), 372 bytes | 0 bytes/s, done.
  
  Total 3 (delta 2), reused 0 (delta 0)
  
  
  
  -----> Fetching custom git buildpack... done
  
  -----> Multipack app detected
  
  =====> Downloading Buildpack: https://github.com/shunjikonishi/heroku-buildpack-ffmpeg.git
  
  =====> Detected Framework: ffmpeg
  
  -----> Install ffmpeg
  
         DOWNLOAD_URL =  http://flect.github.io/heroku-binaries/libs/ffmpeg.tar.gz
  
         exporting PATH and LIBRARY_PATH
  
  =====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-python.git
  
  =====> Detected Framework: Python
  
  -----> Installing dependencies with pip
  
         Cleaning up...
  
  
  
  -----> Preparing static assets
  
         Collectstatic configuration error. To debug, run:
  
         $ heroku run python ./example/manage.py collectstatic --noinput
  
  
  
  Using release configuration from last framework (Python).
  
  -----> Discovering process types
  
         Procfile declares types -> web
  
  
  
  -----> Compressing... done, 198.1MB
  
  -----> Launching... done, v94
  
         http://[redacted].herokuapp.com/ deployed to Heroku
  
  
  
  To git@heroku.com:awe01.git
  
     78d6b68..cd99fef  master -> master
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ heroku run ffmpeg
  
  Running `ffmpeg` attached to terminal... up, run.6408
  
  ffmpeg version git-2013-06-02-5711e4f Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun  2 2013 07:38:40 with gcc 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1)
  
    configuration: --enable-shared --disable-asm --prefix=/app/vendor/ffmpeg
  
    libavutil      52. 34.100 / 52. 34.100
  
    libavcodec     55. 13.100 / 55. 13.100
  
    libavformat    55.  8.102 / 55.  8.102
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 74.101 /  3. 74.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
  
  
  
  Use -h to get full help or, even better, run 'man ffmpeg'
  
  (venv-app)moriartymacbookair13:getstartapp macuser$ heroku run bash
  
  Running `bash` attached to terminal... up, run.9660
  
  ~ $ python
  
  Python 2.7.8 (default, Jul  9 2014, 20:47:08) 
  
  [GCC 4.4.3] on linux2
  
  Type "help", "copyright", "credits" or "license" for more information.
  
  >>> import pydub
  
  >>> from pydub import AudioSegment
  
  >>> exit()
  
  ~ $ which ffmpeg
  
  /app/vendor/ffmpeg/bin/ffmpeg
  
  ~ $ python 
  
  
  
  Python 2.7.8 (default, Jul  9 2014, 20:47:08) 
  
  [GCC 4.4.3] on linux2
  
  Type "help", "copyright", "credits" or "license" for more information.
  
  >>> import pydub
  
  >>> from pydub import AudioSegment
  
  >>> AudioSegment.silent(5000).export("/tmp/asdf.mp3", "mp3")
  
  <open file="file"></open>tmp/asdf.mp3', mode 'wb+' at 0x7f9a37d44780>
  
  >>> exit ()
  
  ~ $ cd /tmp/
  
  /tmp $ ls
  
  asdf.mp3
  
  /tmp $ open asdf.mp3
  
  bash: open: command not found
  
  /tmp $ ls -lah
  
  total 8.0K
  
  drwx------  2 u36483 36483 4.0K 2014-10-22 04:14 .
  
  drwxr-xr-x 14 root   root  4.0K 2014-09-26 07:08 ..
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:14 asdf.mp3

  Note the file size of 0 above for the mp3 file... when I do the same thing on my macbook, the file size is never zero

  Back to the heroku shell :

  /tmp $ python
  
  Python 2.7.8 (default, Jul  9 2014, 20:47:08) 
  
  [GCC 4.4.3] on linux2
  
  Type "help", "copyright", "credits" or "license" for more information.
  
  >>> import pydub
  
  >>> from pydub import AudioSegment
  
  >>> pydub.AudioSegment.ffmpeg = "/app/vendor/ffmpeg/bin/ffmpeg" 
  
  >>> AudioSegment.silence(1200).export("/tmp/herokuSilence.mp3", format="mp3")
  
  Traceback (most recent call last):
  
    File "<stdin>", line 1, in <module>
  
  AttributeError: type object 'AudioSegment' has no attribute 'silence'
  
  >>> AudioSegment.silent(1200).export("/tmp/herokuSilence.mp3", format="mp3")
  
  <open file="file"></open>tmp/herokuSilence.mp3', mode 'wb+' at 0x7fcc2017c780>
  
  >>> exit()
  
  /tmp $ ls
  
  asdf.mp3  herokuSilence.mp3
  
  /tmp $ ls -lah
  
  total 8.0K
  
  drwx------  2 u36483 36483 4.0K 2014-10-22 04:29 .
  
  drwxr-xr-x 14 root   root  4.0K 2014-09-26 07:08 ..
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:14 asdf.mp3
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:29 herokuSilence.mp3
  
  </module></stdin>

  I realised the first time that I had forgotten the pydub.AudioSegment.ffmpeg = "/app/vendor/ffmpeg/bin/ffmpeg" command, but as you can see above, the file is still zero size

  Out of desperation, I even tried adding the ".heroku" into the path to be as verbatim as your example, but that didn’t fix it :

  /tmp $ python
  
  Python 2.7.8 (default, Jul  9 2014, 20:47:08) 
  
  [GCC 4.4.3] on linux2
  
  Type "help", "copyright", "credits" or "license" for more information.
  
  >>> import pydub
  
  >>> from pydub import AudioSegment
  
  >>> pydub.AudioSegment.ffmpeg = "/app/.heroku/vendor/ffmpeg/bin/ffmpeg"
  
  >>> AudioSegment.silent(1200).export("/tmp/herokuSilence03.mp3", format="mp3")
  
  <open file="file"></open>tmp/herokuSilence03.mp3', mode 'wb+' at 0x7fc92aca7780>
  
  >>> exit()
  
  /tmp $ ls -lah
  
  total 8.0K
  
  drwx------  2 u36483 36483 4.0K 2014-10-22 04:31 .
  
  drwxr-xr-x 14 root   root  4.0K 2014-09-26 07:08 ..
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:14 asdf.mp3
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:31 herokuSilence03.mp3
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:29 herokuSilence.mp3

  Finally, I tried exporting a .wav file to check pydub was at least working correctly

  /tmp $ python
  
  Python 2.7.8 (default, Jul  9 2014, 20:47:08) 
  
  [GCC 4.4.3] on linux2
  
  Type "help", "copyright", "credits" or "license" for more information.
  
  >>> import pydub
  
  >>> from pydub import AudioSegment
  
  >>> pydub.AudioSegment.ffmpeg = "/app/vendor/ffmpeg/bin/ffmpeg"
  
  >>> AudioSegment.silent(1300).export("/tmp/heroku_wav_silence01.wav", format="wav")
  
  <open file="file"></open>tmp/heroku_wav_silence01.wav', mode 'wb+' at 0x7fa33cbf3780>
  
  >>> exit()
  
  /tmp $ ls
  
  asdf.mp3  herokuSilence03.mp3  herokuSilence.mp3  heroku_wav_silence01.wav
  
  /tmp $ ls -lah
  
  total 40K
  
  drwx------  2 u36483 36483 4.0K 2014-10-22 04:42 .
  
  drwxr-xr-x 14 root   root  4.0K 2014-09-26 07:08 ..
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:14 asdf.mp3
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:31 herokuSilence03.mp3
  
  -rw-------  1 u36483 36483    0 2014-10-22 04:29 herokuSilence.mp3
  
  -rw-------  1 u36483 36483  29K 2014-10-22 04:42 heroku_wav_silence01.wav
  
  /tmp $ 

  At least that filesize for .wav is non-zero, so pydub is working

  My current theory is that either I’m still not using ffmpeg correctly, or it’s insufficient... maybe I need an mp3 additional install on top of basic ffmpeg.

  Several sites mention "libavcodec-extra-53" but I’m not sure how to install that on heroku, or to check if I have it ? https://github.com/jiaaro/pydub/issues/36
  Similarly tutorials on libmp3lame seem to be geared towards laptop installation rather than installation on heroku, so I’m at a loss http://superuser.com/questions/196857/how-to-install-libmp3lame-for-ffmpeg

  In case relevant, I also have youtube-dl in my requirements.txt... this also works locally on my macbook, but fails when I run it in the heroku shell :

  ~/ytdl $ youtube-dl --restrict-filenames -x --audio-format mp3 n2anDgdUHic
  
  [youtube] Setting language
  
  [youtube] Confirming age
  
  [youtube] n2anDgdUHic: Downloading webpage
  
  [youtube] n2anDgdUHic: Downloading video info webpage
  
  [youtube] n2anDgdUHic: Extracting video information
  
  [download] Destination: Boyce_Avenue_feat._Megan_Nicole_-_Skyscraper_Patrick_Ebert_Edit-n2anDgdUHic.m4a
  
  [download] 100% of 5.92MiB in 00:00
  
  [ffmpeg] Destination: Boyce_Avenue_feat._Megan_Nicole_-_Skyscraper_Patrick_Ebert_Edit-n2anDgdUHic.mp3
  
  ERROR: audio conversion failed: Unknown encoder 'libmp3lame'
  
  ~/ytdl $ 

  The informative link is that it too specificies an mp3 failure, so perhaps they two issues are related.

  ---

  EDIT 2

  See answer, all problems solved