audioresample
audioresample resamples raw audio buffers to different sample rates using a configurable windowing function to enhance quality.
By default, the resampler uses a reduced sinc table, with cubic interpolation filling in the gaps. This ensures that the table does not become too big. However, the interpolation increases the CPU usage considerably. As an alternative, a full sinc table can be used. Doing so can drastically reduce CPU usage (4x faster with 44.1 -> 48 kHz conversions for example), at the cost of increased memory consumption, plus the sinc table takes longer to initialize when the element is created. A third mode exists, which uses the full table unless said table would become too large, in which case the interpolated one is used instead.
Example launch line
gst-launch-1.0 -v uridecodebin uri=file:///path/to/audio.ogg ! audioconvert ! audioresample ! audio/x-raw, rate=8000 ! autoaudiosink
Decode an audio file and downsample it to 8Khz and play sound. To create the Ogg/Vorbis file refer to the documentation of vorbisenc. This assumes there is an audio sink that will accept/handle 8kHz audio.
Hierarchy
GObject ╰──GInitiallyUnowned ╰──GstObject ╰──GstElement ╰──GstBaseTransform ╰──audioresample
Factory details
Authors: – Sebastian Dröge
Classification: – Filter/Converter/Audio
Rank – primary
Plugin – audioresample
Package – GStreamer Base Plug-ins
Pad Templates
sink
audio/x-raw:
format: { F64LE, F64BE, F32LE, F32BE, S32LE, S32BE, U32LE, U32BE, S24_32LE, S24_32BE, U24_32LE, U24_32BE, S24LE, S24BE, U24LE, U24BE, S20LE, S20BE, U20LE, U20BE, S18LE, S18BE, U18LE, U18BE, S16LE, S16BE, U16LE, U16BE, S8, U8 }
rate: [ 1, 2147483647 ]
channels: [ 1, 2147483647 ]
layout: { (string)interleaved, (string)non-interleaved }
src
audio/x-raw:
format: { F64LE, F64BE, F32LE, F32BE, S32LE, S32BE, U32LE, U32BE, S24_32LE, S24_32BE, U24_32LE, U24_32BE, S24LE, S24BE, U24LE, U24BE, S20LE, S20BE, U20LE, U20BE, S18LE, S18BE, U18LE, U18BE, S16LE, S16BE, U16LE, U16BE, S8, U8 }
rate: [ 1, 2147483647 ]
channels: [ 1, 2147483647 ]
layout: { (string)interleaved, (string)non-interleaved }
Properties
quality
“quality” gint
Resample quality with 0 being the lowest and 10 being the best
Flags : Read / Write / Construct
Default value : 4
resample-method
“resample-method” GstAudioResamplerMethod *
What resample method to use
Flags : Read / Write
Default value : kaiser (4)
sinc-filter-auto-threshold
“sinc-filter-auto-threshold” guint
Memory usage threshold to use if sinc filter mode is AUTO, given in bytes
Flags : Read / Write
Default value : 1048576
sinc-filter-interpolation
“sinc-filter-interpolation” GstAudioResamplerFilterInterpolation *
How to interpolate the sinc filter table
Flags : Read / Write
Default value : cubic (2)
sinc-filter-mode
“sinc-filter-mode” GstAudioResamplerFilterMode *
What sinc filter table mode to use
Flags : Read / Write
Default value : auto (2)
Named constants
Audio-resampler-filter-interpolation
Members
none
(0) – GST_AUDIO_RESAMPLER_FILTER_INTERPOLATION_NONE
linear
(1) – GST_AUDIO_RESAMPLER_FILTER_INTERPOLATION_LINEAR
cubic
(2) – GST_AUDIO_RESAMPLER_FILTER_INTERPOLATION_CUBIC
Audio-resampler-filter-mode
Members
interpolated
(0) – GST_AUDIO_RESAMPLER_FILTER_MODE_INTERPOLATED
full
(1) – GST_AUDIO_RESAMPLER_FILTER_MODE_FULL
auto
(2) – GST_AUDIO_RESAMPLER_FILTER_MODE_AUTO
Audio-resampler-method
Members
nearest
(0) – GST_AUDIO_RESAMPLER_METHOD_NEAREST
linear
(1) – GST_AUDIO_RESAMPLER_METHOD_LINEAR
cubic
(2) – GST_AUDIO_RESAMPLER_METHOD_CUBIC
blackman-nuttall
(3) – GST_AUDIO_RESAMPLER_METHOD_BLACKMAN_NUTTALL
kaiser
(4) – GST_AUDIO_RESAMPLER_METHOD_KAISER
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