[FFmpeg-user] man page vs. online documentation

Jim Worrall coniophora at gmail.com
Fri Dec 2 03:18:02 CET 2011

On Dec 1, 2011, at 6:38 PM, Clément Bœsch wrote:

On Thu, Dec 01, 2011 at 05:26:56PM -0700, Jim Worrall wrote:
> I recently compiled and installed the latest ffmpeg, and compared the man
> page that came with it to the current ffmpeg documentation online at
> http://ffmpeg.org/ffmpeg.html .  It seems like basically the same document,
> but there are many significant differences.

The online documentation is based on the upstream (each time the
documentation gets updated in the repository, the online one is

What are you calling latest FFmpeg? Source snapshot or latest stable
(0.8.7 ATM)?

> Which one is likely to better reflect the instructions for the actual
> one I install, the man page that accompanies it, or the online
> documentation at the time I downloaded it?

It depends; typo fix, wording improvements, or anything such as new
examples for old features are likely to apply as well on your version (and
ideally they are backported so you don't actually need to look in the
online one).  OTOH, new features only available in the "dev" version won't
apply to the one you just downloaded.

Maybe you should be more specific about the differences you noticed?

I guess when I got the "latest", I browsed and chose the 0.8.7 (not sure
what ATM means in this context).  I don't really understand the development/
version process.  Here's how my ffmpeg self-identifies:
ffmpeg version 0.8.7, Copyright (c) 2000-2011 the FFmpeg developers
  built on Nov 30 2011 19:37:44 with clang 3.0 (tags/Apple/clang-211.12)
  configuration: --prefix=/Volumes/Ramdisk/sw --cc=clang --enable-gpl --enable-pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --arch=x86_64 --enable-runtime-cpudetect
  libavutil    51.  9. 1 / 51.  9. 1
  libavcodec   53.  8. 0 / 53.  8. 0
  libavformat  53.  5. 0 / 53.  5. 0
  libavdevice  53.  1. 1 / 53.  1. 1
  libavfilter   2. 23. 0 /  2. 23. 0
  libswscale    2.  0. 0 /  2.  0. 0
  libpostproc  51.  2. 0 / 51.  2. 0

Here are some differences:
The man page has a sentence in the Description about converting as lossless as 
possible; this is not online.
The online page has an entire section on Stream Selection after the Description;
not in the man page.
The online page has an extensive section on Stream Specifiers, under Options;
not found in the man page.
The online page has a section called AVOptions under Options;
not found in the man page.
There seem to be additional Main Options in the online page not found in the man page,
for example:
	'-n (global)’
	‘-c[:stream_specifier] codec (input/output,per-stream)’
	‘-codec[:stream_specifier] codec (input/output,per-stream)’
These examples are just from the early part of the manual, there are many more, and
they seem pretty substantial.

So maybe these changes were introduced after the 0.8.7 release?
Is it better to get the latest snapshot?
Thank you.

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