audioresample

audioresample — Resamples audio

Synopsis

struct              GstAudioResample;

Object Hierarchy

  GObject
   +----GInitiallyUnowned
         +----GstObject
               +----GstElement
                     +----GstBaseTransform
                           +----GstAudioResample

Properties

  "filter-length"            gint                  : Read / Write
  "quality"                  gint                  : Read / Write / Construct
  "sinc-filter-auto-threshold" guint                 : Read / Write
  "sinc-filter-mode"         SpeexResamplerSincFilterMode  : Read / Write

Description

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

1
gst-launch -v filesrc location=sine.ogg ! oggdemux ! vorbisdec ! audioconvert ! audioresample ! audio/x-raw, rate=8000 ! alsasink
Decode an Ogg/Vorbis downsample to 8Khz and play sound through alsa. To create the Ogg/Vorbis file refer to the documentation of vorbisenc.

Synopsis

Element Information

plugin

audioresample

author

Sebastian Dröge <sebastian.droege@collabora.co.uk>

class

Filter/Converter/Audio

Element Pads

name

sink

direction

sink

presence

always

details

audio/x-raw, format=(string){ F32LE, F64LE, S32LE, S24LE, S16LE, S8 }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string){ interleaved, non-interleaved }

name

src

direction

source

presence

always

details

audio/x-raw, format=(string){ F32LE, F64LE, S32LE, S24LE, S16LE, S8 }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string){ interleaved, non-interleaved }

Details

struct GstAudioResample

struct GstAudioResample;

Opaque data structure.

Property Details

The "filter-length" property

  "filter-length"            gint                  : Read / Write

Length of the resample filter.

Allowed values: >= 0

Default value: 64


The "quality" property

  "quality"                  gint                  : Read / Write / Construct

Resample quality with 0 being the lowest and 10 being the best.

Allowed values: [0,10]

Default value: 4


The "sinc-filter-auto-threshold" property

  "sinc-filter-auto-threshold" guint                 : Read / Write

Memory usage threshold to use if sinc filter mode is AUTO, given in bytes.

Default value: 1048576


The "sinc-filter-mode" property

  "sinc-filter-mode"         SpeexResamplerSincFilterMode  : Read / Write

What sinc filter table mode to use.

Default value: Use full table if table size below threshold