alsa_enc.c File Reference

ALSA input and output: output. More...

#include <alsa/asoundlib.h>
#include "libavutil/frame.h"
#include "libavutil/internal.h"
#include "libavutil/time.h"
#include "libavformat/internal.h"
#include "libavformat/mux.h"
#include "avdevice.h"
#include "alsa.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)
static int	audio_get_device_list (AVFormatContext *h, AVDeviceInfoList *device_list)

Variables
static const AVClass	alsa_muxer_class
const FFOutputFormat	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 can 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_enc.c.

Function Documentation

audio_write_header()

static av_cold int audio_write_header ( AVFormatContext * s1 )

static

Definition at line 52 of file alsa_enc.c.

audio_write_packet()

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

static

Definition at line 85 of file alsa_enc.c.

Referenced by audio_write_frame().

audio_write_frame()

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

static

Definition at line 121 of file alsa_enc.c.

audio_get_output_timestamp()

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

static

Definition at line 140 of file alsa_enc.c.

audio_get_device_list()

static int audio_get_device_list ( AVFormatContext * h, AVDeviceInfoList * device_list )

static

Definition at line 150 of file alsa_enc.c.

Variable Documentation

alsa_muxer_class

const AVClass alsa_muxer_class

static

Initial value:

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

Definition at line 155 of file alsa_enc.c.

ff_alsa_muxer

const FFOutputFormat ff_alsa_muxer

Initial value:

= {
    .p.name         = "alsa",
    .p.long_name    = NULL_IF_CONFIG_SMALL("ALSA audio output"),
    .priv_data_size = sizeof(AlsaData),
    .p.audio_codec  = DEFAULT_CODEC_ID,
    .p.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_device_list = audio_get_device_list,
    .get_output_timestamp = audio_get_output_timestamp,
    .p.flags        = AVFMT_NOFILE,
    .p.priv_class   = &alsa_muxer_class,
}

Definition at line 162 of file alsa_enc.c.