diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2015-04-09 21:36:42 +0200 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2015-04-09 21:36:42 +0200 |
commit | b1b58310d09297eb8e64b156e6da3406bc866cce (patch) | |
tree | 9314f08b45e3e58b6afb667d4f30a05dabe497e0 /libavdevice/alsa_dec.c | |
parent | 259fd4c7cfb8afbb022921b44fe6611fcefff3b1 (diff) | |
parent | 8d26c193fb42d08602ac93ece039d4718d029adc (diff) | |
download | ffmpeg-b1b58310d09297eb8e64b156e6da3406bc866cce.tar.gz |
Merge commit '8d26c193fb42d08602ac93ece039d4718d029adc'
* commit '8d26c193fb42d08602ac93ece039d4718d029adc':
avdevice: Apply a more consistent file naming scheme
Conflicts:
libavdevice/Makefile
libavdevice/alsa.h
libavdevice/alsa_dec.c
libavdevice/alsa_enc.c
libavdevice/sndio_enc.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavdevice/alsa_dec.c')
-rw-r--r-- | libavdevice/alsa_dec.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/libavdevice/alsa_dec.c b/libavdevice/alsa_dec.c new file mode 100644 index 0000000000..286af650c7 --- /dev/null +++ b/libavdevice/alsa_dec.c @@ -0,0 +1,168 @@ +/* + * ALSA input and output + * Copyright (c) 2007 Luca Abeni ( lucabe72 email it ) + * Copyright (c) 2007 Benoit Fouet ( benoit fouet free fr ) + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * ALSA input and output: input + * @author Luca Abeni ( lucabe72 email it ) + * @author Benoit Fouet ( benoit fouet free fr ) + * @author Nicolas George ( nicolas george normalesup org ) + * + * This avdevice decoder allows to capture audio from 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 capture period is set to the lower value available for the device, + * which gives a low latency suitable for real-time capture. + * + * The PTS are an Unix time in microsecond. + * + * Due to a bug in the ALSA library + * (https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4308), this + * decoder does not work with certain ALSA plugins, especially the dsnoop + * plugin. + */ + +#include <alsa/asoundlib.h> + +#include "libavutil/internal.h" +#include "libavutil/mathematics.h" +#include "libavutil/opt.h" +#include "libavutil/time.h" + +#include "libavformat/internal.h" + +#include "avdevice.h" +#include "alsa.h" + +static av_cold int audio_read_header(AVFormatContext *s1) +{ + AlsaData *s = s1->priv_data; + AVStream *st; + int ret; + enum AVCodecID codec_id; + + st = avformat_new_stream(s1, NULL); + if (!st) { + av_log(s1, AV_LOG_ERROR, "Cannot add stream\n"); + + return AVERROR(ENOMEM); + } + codec_id = s1->audio_codec_id; + + ret = ff_alsa_open(s1, SND_PCM_STREAM_CAPTURE, &s->sample_rate, s->channels, + &codec_id); + if (ret < 0) { + return AVERROR(EIO); + } + + /* take real parameters */ + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->codec_id = codec_id; + st->codec->sample_rate = s->sample_rate; + st->codec->channels = s->channels; + st->codec->frame_size = s->frame_size; + avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */ + /* microseconds instead of seconds, MHz instead of Hz */ + s->timefilter = ff_timefilter_new(1000000.0 / s->sample_rate, + s->period_size, 1.5E-6); + if (!s->timefilter) + goto fail; + + return 0; + +fail: + snd_pcm_close(s->h); + return AVERROR(EIO); +} + +static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt) +{ + AlsaData *s = s1->priv_data; + int res; + int64_t dts; + snd_pcm_sframes_t delay = 0; + + if (av_new_packet(pkt, s->period_size * s->frame_size) < 0) { + return AVERROR(EIO); + } + + while ((res = snd_pcm_readi(s->h, pkt->data, s->period_size)) < 0) { + if (res == -EAGAIN) { + av_free_packet(pkt); + + return AVERROR(EAGAIN); + } + if (ff_alsa_xrun_recover(s1, res) < 0) { + av_log(s1, AV_LOG_ERROR, "ALSA read error: %s\n", + snd_strerror(res)); + av_free_packet(pkt); + + return AVERROR(EIO); + } + ff_timefilter_reset(s->timefilter); + } + + dts = av_gettime(); + snd_pcm_delay(s->h, &delay); + dts -= av_rescale(delay + res, 1000000, s->sample_rate); + pkt->pts = ff_timefilter_update(s->timefilter, dts, s->last_period); + s->last_period = res; + + pkt->size = res * s->frame_size; + + return 0; +} + +static int audio_get_device_list(AVFormatContext *h, AVDeviceInfoList *device_list) +{ + return ff_alsa_get_device_list(device_list, SND_PCM_STREAM_CAPTURE); +} + +static const AVOption options[] = { + { "sample_rate", "", offsetof(AlsaData, sample_rate), AV_OPT_TYPE_INT, {.i64 = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }, + { "channels", "", offsetof(AlsaData, channels), AV_OPT_TYPE_INT, {.i64 = 2}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }, + { NULL }, +}; + +static const AVClass alsa_demuxer_class = { + .class_name = "ALSA demuxer", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, + .category = AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT, +}; + +AVInputFormat ff_alsa_demuxer = { + .name = "alsa", + .long_name = NULL_IF_CONFIG_SMALL("ALSA audio input"), + .priv_data_size = sizeof(AlsaData), + .read_header = audio_read_header, + .read_packet = audio_read_packet, + .read_close = ff_alsa_close, + .get_device_list = audio_get_device_list, + .flags = AVFMT_NOFILE, + .priv_class = &alsa_demuxer_class, +}; |