parent
f62abbf3b7
commit
e903cb4194
3 changed files with 262 additions and 1 deletions
@ -0,0 +1,198 @@ |
||||
\input texinfo @c -*- texinfo -*- |
||||
|
||||
@settitle FFmpeg Resampler Documentation |
||||
@titlepage |
||||
@center @titlefont{FFmpeg Resampler Documentation} |
||||
@end titlepage |
||||
|
||||
@top |
||||
|
||||
@contents |
||||
|
||||
@chapter Description |
||||
@c man begin DESCRIPTION |
||||
|
||||
The FFmpeg resampler provides an high-level interface to the |
||||
libswresample library audio resampling utilities. In particular it |
||||
allows to perform audio resampling, audio channel layout rematrixing, |
||||
and convert audio format and packing layout. |
||||
|
||||
@c man end DESCRIPTION |
||||
|
||||
@chapter Resampler Options |
||||
@c man begin RESAMPLER OPTIONS |
||||
|
||||
The audio resampler supports the following named options. |
||||
|
||||
Options may be set by specifying -@var{option} @var{value} in the |
||||
FFmpeg tools, or by setting the value explicitly in the |
||||
@code{SwrContext} options or using the @file{libavutil/opt.h} API for |
||||
programmatic use. |
||||
|
||||
@table @option |
||||
|
||||
@item ich, in_channel_count |
||||
Set the number of input channels. Default value is 0. Setting this |
||||
value is not mandatory if the corresponding channel layout |
||||
@option{in_channel_layout} is set. |
||||
|
||||
@item och, out_channel_count |
||||
Set the number of output channels. Default value is 0. Setting this |
||||
value is not mandatory if the corresponding channel layout |
||||
@option{out_channel_layout} is set. |
||||
|
||||
@item uch, used_channel_count |
||||
Set the number of used channels. Default value is 0. This option is |
||||
only used for special remapping. |
||||
|
||||
@item isr, in_sample_rate |
||||
Set the input sample rate. Default value is 0. |
||||
|
||||
@item osr, out_sample_rate |
||||
Set the output sample rate. Default value is 0. |
||||
|
||||
@item isf, in_sample_fmt |
||||
Specify the input sample format. Must be an integer representing the |
||||
corresponding sample format specified in |
||||
@file{libavutil/samplefmt.h} header. Default value is -1 |
||||
(corresponding to @code{AV_SAMPLE_FMT_NONE}). |
||||
|
||||
@item osf, out_sample_fmt |
||||
Specify the output sample format. Must be an integer representing the |
||||
corresponding sample format specified in |
||||
@file{libavutil/samplefmt.h} header. Default value is -1 |
||||
(corresponding to @code{AV_SAMPLE_FMT_NONE}). |
||||
|
||||
@item tsf, internal_sample_fmt |
||||
Set the internal sample format. Default value is -1. |
||||
|
||||
@item icl, in_channel_layout |
||||
Set the input channel layout. |
||||
|
||||
@item ocl, out_channel_layout |
||||
Set the output channel layout. |
||||
|
||||
@item clev, center_mix_level |
||||
Set center mix level. It is a value expressed in deciBel, and must be |
||||
inclusively included between -32 and +32. |
||||
|
||||
@item slev, surround_mix_level |
||||
Set surround mix level. It is a value expressed in deciBel, and must |
||||
be inclusively included between -32 and +32. |
||||
|
||||
@item lfe_mix_evel |
||||
Set LFE mix level. |
||||
|
||||
@item rmvol, rematrix_volume |
||||
Set rematrix volume. Default value is 1.0. |
||||
|
||||
@item flags, swr_flags |
||||
Set flags used by the converter. Default value is 0. |
||||
|
||||
It supports the following individual flags: |
||||
@table @option |
||||
@item res |
||||
force resampling |
||||
@end table |
||||
|
||||
@item dither_scale |
||||
Set the dither scale. Default value is 1. |
||||
|
||||
@item dither_method |
||||
Set dither method. Default value is 0. |
||||
|
||||
Supported values: |
||||
@table @samp |
||||
@item rectangular |
||||
select rectangular dither |
||||
@item triangular |
||||
select triangular dither |
||||
@item triangular_hp |
||||
select triangular dither with high pass |
||||
@end table |
||||
|
||||
@item filter_size |
||||
Set resampling filter size, default value is 16. |
||||
|
||||
@item phase_shift |
||||
Set resampling phase shift, default value is 10, must be included |
||||
between 0 and 30. |
||||
|
||||
@item linear_interp |
||||
Use Linear Interpolation if set to 1, default value is 0. |
||||
|
||||
@item cutoff |
||||
Set cutoff frequency ratio. Must be a float value between 0 and 1, |
||||
default value is 0.8. |
||||
|
||||
@item min_comp |
||||
Set minimum difference between timestamps and audio data (in seconds) |
||||
below which no timestamp compensation of either kind is applied. |
||||
Default value is @code{FLT_MAX}. |
||||
|
||||
@item min_hard_comp |
||||
Set minimum difference between timestamps and audio data (in seconds) |
||||
to trigger padding/trimming the data. Must be a non-negative double, |
||||
default value is 0.1. |
||||
|
||||
@item comp_duration |
||||
Set duration (in seconds) over which data is stretched/squeezed to |
||||
make it match the timestamps. Must be a non-negative double float |
||||
value, default value is 1.0. |
||||
|
||||
@item max_soft_comp |
||||
Set maximum factor by which data is stretched/squeezed to make it |
||||
match the timestamps. Must be a non-negative double float value, |
||||
default value is 0. |
||||
|
||||
@item matrix_encoding |
||||
Select matrixed stereo encoding. |
||||
|
||||
It accepts the following values: |
||||
@table @samp |
||||
@item none |
||||
select none |
||||
@item dolby |
||||
select Dolby |
||||
@item dplii |
||||
select Dolby Pro Logic II |
||||
@end table |
||||
|
||||
Default value is @code{none}. |
||||
|
||||
@item filter_type |
||||
Select resampling filter type. This only affects resampling |
||||
operations. |
||||
|
||||
It accepts the following values: |
||||
@table @samp |
||||
@item cubic |
||||
select cubic |
||||
@item blackman_nuttall |
||||
select Blackman Nuttall Windowed Sinc |
||||
@item kaiser |
||||
select Kaiser Windowed Sinc |
||||
@end table |
||||
|
||||
@item kaiser_beta |
||||
Set Kaiser Window Beta value. Must be an integer included between 2 |
||||
and 16, default value is 9. |
||||
|
||||
@end table |
||||
|
||||
@c man end RESAMPLER OPTIONS |
||||
|
||||
@ignore |
||||
|
||||
@setfilename ffmpeg-resampler |
||||
@settitle FFmpeg Resampler |
||||
|
||||
@c man begin SEEALSO |
||||
ffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), libswresample(3) |
||||
@c man end |
||||
|
||||
@c man begin AUTHORS |
||||
See Git history (git://source.ffmpeg.org/ffmpeg) |
||||
@c man end |
||||
|
||||
@end ignore |
@ -0,0 +1,62 @@ |
||||
\input texinfo @c -*- texinfo -*- |
||||
|
||||
@settitle Libswresample Documentation |
||||
@titlepage |
||||
@center @titlefont{Libswresample Documentation} |
||||
@end titlepage |
||||
|
||||
@top |
||||
|
||||
@contents |
||||
|
||||
@chapter Description |
||||
@c man begin DESCRIPTION |
||||
|
||||
The libswresample library performs highly optimized audio resampling, |
||||
rematrixing and sample format conversion operations. |
||||
|
||||
Specifically, this library performs the following conversions: |
||||
|
||||
@itemize |
||||
@item |
||||
@emph{Resampling}: is the process of changing the audio rate, for |
||||
example from an high sample rate of 44100Hz to 8000Hz. Audio |
||||
conversion from high to low sample rate is a lossy process. Several |
||||
resampling options and algorithms are available. |
||||
|
||||
@item |
||||
@emph{Format conversion}: is the process of converting the type of |
||||
samples, for example from 16-bit signed samples to unsigned 8-bit or |
||||
float samples. It also handles packing conversion, when passing from |
||||
packed layout (all samples belonging to distinct channels interleaved |
||||
in the same buffer), to planar layout (all samples belonging to the |
||||
same channel stored in a dedicated buffer or "plane"). |
||||
|
||||
@item |
||||
@emph{Rematrixing}: is the process of changing the channel layout, for |
||||
example from stereo to mono. When the input channels cannot be mapped |
||||
to the output streams, the process is lossy, since it involves |
||||
different gain factors and mixing. |
||||
@end itemize |
||||
|
||||
Various other audio conversions (e.g. stretching and padding) are |
||||
enabled through dedicated options. |
||||
|
||||
@c man end DESCRIPTION |
||||
|
||||
@ignore |
||||
|
||||
@setfilename libswresample |
||||
@settitle audio resampling library |
||||
|
||||
@c man begin SEEALSO |
||||
ffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), ffmpeg-resampler(1), libavutil(3) |
||||
@c man end |
||||
|
||||
@c man begin AUTHORS |
||||
See Git history (git://source.ffmpeg.org/ffmpeg) |
||||
@c man end |
||||
|
||||
@end ignore |
||||
|
||||
@bye |
Loading…
Reference in new issue