This list is mainly useful to be directly used as a parameter by the
audio sink buffer, when there is no need to force a specific channel
layout.
The list of formats is generated programmatically, and avoids channel
layouts not supported by libavfilter (with more than 8 channels).
We preferred to avoid compile-time generation in order to avoid some
unnecessary complexity (build hacks, generating code maintainance
etc.).
A more compact way to express this list through the use of macros
should be possible when libavfilter will support more than 8 channels,
as there will be no need to filter out channel layouts with more than
8 channels.
See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: add ff_all_channel_layouts internal symbol
Date: Sat, 20 Aug 2011 15:33:16 +0200
A function name should tell what the function does rather than what
the function returns. This also avoids possible conflicts
(e.g. between a function and a public list of all supported formats),
and clarifies the code.
Breaks audio API/ABI, add a backward compatibility layer for video
API/ABI.
These changes were forgotten in commits:
lavfi: simplify signature for avfilter_get_audio_buffer() and friends
(commit 2c0317419b)
and
lavfi: consistently use int for sample_rate in AVFilterLink and AVFilterBufferRefAudioProps
(commit 4381bddc9f)
The additional parameters were never used and are complicating the
function interface. Also, they were inconsistent with the way the
video API works.
So this assumes that a requested samples buffer will have *always* the
format specified in the requested link.
This breaks audio filtering API and ABI.
Merge video_qscale (set by -qscale) and audio_qscale (set by -aq) into
one 'qscale' field in the options context. Add a shortcut -q for -qscale
and make -aq an alias for -q:a.
The libavfilter SOC SVN repo is badly outdated, and some filters
supports a syntax different from the current code, so it is better do
not misled users into using it and just drop its reference.
This is done in order to clarify the non-video-specific nature of the
buffersink code, as the result of the video/audio API unification of
the previous commit, and for improving overall consistency.
The new API is more generic (no distinction between audio/video for
pulling frames), and avoids code duplication.
A backward compatibility layer is kept for avoiding tools ABI breaks
(only for the video binary interface, audio interface was never used
in the tools).
Transforms the loose enumeration of issues that was to far below
in the text into a more verbose paragraph at the top. The new text
also mentions the possibility to propose new types of issues to
track on the development mailing list.
Signed-off-by: Alexander Strasser <eclipse7@gmx.net>
This change makes the first part of the file easier to read quickly.
It makes it also easier to spot the URLs which might be one of the main
interests of many readers.
Signed-off-by: Alexander Strasser <eclipse7@gmx.net>
Correct a few grammar and spelling errors. Also improve consistency
by always referring to substatus (not substate).
Signed-off-by: Alexander Strasser <eclipse7@gmx.net>