Allow a custom ffmpeg path to be specified

youtube-dl: 2014.01.07.5 python: 2.7.3 OS: Ubuntu 12.04

Great work on providing a way to join DASH audio and video!

I know it hasn’t been announced yet, but I thought I’d report a possible issue related to it. The ffmpeg/avconv on Ubuntu 12.04 doesn’t seem to mux the streams correctly:

youtube-dl -f ‘137+140’ gBabKoHSErI

produces an .mp4 file with an audio track but no video track:

> mediainfo gBabKoHSErI.mp4

General
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom
File size                                : 2.16 MiB
Duration                                 : 2mn 21s
Overall bit rate mode                    : Variable
Overall bit rate                         : 128 Kbps
Encoded date                             : UTC 2013-12-27 19:27:06
Tagged date                              : UTC 2013-12-27 19:27:06
Writing application                      : Lavf53.21.1

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 2mn 21s
Bit rate mode                            : Variable
Bit rate                                 : 126 Kbps
Channel count                            : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 44.1 KHz
Compression mode                         : Lossy
Stream size                              : 2.11 MiB (98%)
Encoded date                             : UTC 2013-12-27 19:27:06
Tagged date                              : UTC 2013-12-27 19:27:06

I get an error if I try to merge the streams manually with the stock ffmpeg e.g.:

> ffmpeg -version
ffmpeg version 0.8.9-4:0.8.9-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:12:07 with gcc 4.6.3

> ffmpeg -y -i gBabKoHSErI.f140.m4a -i gBabKoHSErI.f137.mp4 -c copy gBabKoHSErI.mp4
Unrecognized option 'c'
Failed to set value 'copy' for option 'c'

I get the audio-only file (and no error) if I replace -c copy with -acodec copy -vcodec copy.

Both options work fine if I use a more recent version of ffmpeg:

> sffmpeg -version
ffmpeg version 2.0
built on Aug 20 2013 01:54:29 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)

> sffmpeg -y -i gBabKoHSErI.f140.m4a -i gBabKoHSErI.f137.mp4 -c copy gBabKoHSErI.mp4
Stream mapping:
  Stream #1:0 -> #0:0 (copy)
  Stream #0:0 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 3379 fps=0.0 q=-1.0 Lsize=   51389kB time=00:02:21.03 bitrate=2984.9kbits/s    
video:49127kB audio:2162kB subtitle:0 global headers:0kB muxing overhead 0.195621%

An option to set the ffmpeg path would allow me to use the more recent ffmpeg automatically; it would also allow users to make their own choices re: avconv vs ffmpeg.

[phihag]

Since youtube-dl 2015.02.16, you can use the --ffmpeg-location option to specify the path of the executable (or the directory the executable resides in). See our FAQ if you need help updating.

[darkuranium]

@HarrySykes7890 'ffmpeg_location': ... in the configuration dictionary.

It’s not documented in YoutubeDL.py for some reason, I’m guessing oversight?