alsa-audio-enc.c File Reference

ALSA input and output: output. More...

#include <alsa/asoundlib.h>
#include "libavutil/time.h"
#include "libavformat/internal.h"
#include "avdevice.h"
#include "alsa-audio.h"

Go to the source code of this file.

Functions
static av_cold int	audio_write_header (AVFormatContext *s1)
static int	audio_write_packet (AVFormatContext *s1, AVPacket *pkt)
static int	audio_write_frame (AVFormatContext *s1, int stream_index, AVFrame **frame, unsigned flags)
static void	audio_get_output_timestamp (AVFormatContext *s1, int stream, int64_t *dts, int64_t *wall)

Variables
static const AVClass	alsa_muxer_class
AVOutputFormat	ff_alsa_muxer

Detailed Description

ALSA input and output: output.

Author

Luca Abeni ( lucabe72 email it )

Benoit Fouet ( benoit fouet free fr )

This avdevice encoder allows to play audio to an ALSA (Advanced Linux Sound Architecture) device.

The filename parameter is the name of an ALSA PCM device capable of capture, for example "default" or "plughw:1"; see the ALSA documentation for naming conventions. The empty string is equivalent to "default".

The playback period is set to the lower value available for the device, which gives a low latency suitable for real-time playback.

Definition in file alsa-audio-enc.c.

Function Documentation

static av_cold int audio_write_header ( AVFormatContext *  s1 )

static

Definition at line 47 of file alsa-audio-enc.c.

static int audio_write_packet ( AVFormatContext *  s1, AVPacket *  pkt  )

static

Definition at line 80 of file alsa-audio-enc.c.

Referenced by audio_write_frame().

static int audio_write_frame ( AVFormatContext *  s1, int  stream_index, AVFrame **  frame, unsigned  flags  )

static

Definition at line 116 of file alsa-audio-enc.c.

static void audio_get_output_timestamp ( AVFormatContext *  s1, int  stream, int64_t *  dts, int64_t *  wall  )

static

Definition at line 135 of file alsa-audio-enc.c.

Variable Documentation

const AVClass alsa_muxer_class

static

Initial value:

= {
    .class_name     = "ALSA muxer",
    .item_name      = av_default_item_name,
    .version        = LIBAVUTIL_VERSION_INT,
    .category       = AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
}

Definition at line 145 of file alsa-audio-enc.c.

AVOutputFormat ff_alsa_muxer

Initial value:

= {
    .name           = "alsa",
    .long_name      = NULL_IF_CONFIG_SMALL("ALSA audio output"),
    .priv_data_size = sizeof(AlsaData),
    .audio_codec    = DEFAULT_CODEC_ID,
    .video_codec    = AV_CODEC_ID_NONE,
    .write_header   = audio_write_header,
    .write_packet   = audio_write_packet,
    .write_trailer  = ff_alsa_close,
    .write_uncoded_frame = audio_write_frame,
    .get_output_timestamp = audio_get_output_timestamp,
    .flags          = AVFMT_NOFILE,
    .priv_class     = &alsa_muxer_class,
}

Definition at line 152 of file alsa-audio-enc.c.