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2ba45a60 DM |
1 | /* |
2 | * ALSA input and output | |
3 | * Copyright (c) 2007 Luca Abeni ( lucabe72 email it ) | |
4 | * Copyright (c) 2007 Benoit Fouet ( benoit fouet free fr ) | |
5 | * | |
6 | * This file is part of FFmpeg. | |
7 | * | |
8 | * FFmpeg is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * FFmpeg is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with FFmpeg; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
23 | /** | |
24 | * @file | |
25 | * ALSA input and output: output | |
26 | * @author Luca Abeni ( lucabe72 email it ) | |
27 | * @author Benoit Fouet ( benoit fouet free fr ) | |
28 | * | |
29 | * This avdevice encoder allows to play audio to an ALSA (Advanced Linux | |
30 | * Sound Architecture) device. | |
31 | * | |
32 | * The filename parameter is the name of an ALSA PCM device capable of | |
33 | * capture, for example "default" or "plughw:1"; see the ALSA documentation | |
34 | * for naming conventions. The empty string is equivalent to "default". | |
35 | * | |
36 | * The playback period is set to the lower value available for the device, | |
37 | * which gives a low latency suitable for real-time playback. | |
38 | */ | |
39 | ||
40 | #include <alsa/asoundlib.h> | |
41 | ||
42 | #include "libavutil/time.h" | |
43 | #include "libavformat/internal.h" | |
44 | #include "avdevice.h" | |
45 | #include "alsa-audio.h" | |
46 | ||
47 | static av_cold int audio_write_header(AVFormatContext *s1) | |
48 | { | |
49 | AlsaData *s = s1->priv_data; | |
50 | AVStream *st = NULL; | |
51 | unsigned int sample_rate; | |
52 | enum AVCodecID codec_id; | |
53 | int res; | |
54 | ||
55 | if (s1->nb_streams != 1 || s1->streams[0]->codec->codec_type != AVMEDIA_TYPE_AUDIO) { | |
56 | av_log(s1, AV_LOG_ERROR, "Only a single audio stream is supported.\n"); | |
57 | return AVERROR(EINVAL); | |
58 | } | |
59 | st = s1->streams[0]; | |
60 | ||
61 | sample_rate = st->codec->sample_rate; | |
62 | codec_id = st->codec->codec_id; | |
63 | res = ff_alsa_open(s1, SND_PCM_STREAM_PLAYBACK, &sample_rate, | |
64 | st->codec->channels, &codec_id); | |
65 | if (sample_rate != st->codec->sample_rate) { | |
66 | av_log(s1, AV_LOG_ERROR, | |
67 | "sample rate %d not available, nearest is %d\n", | |
68 | st->codec->sample_rate, sample_rate); | |
69 | goto fail; | |
70 | } | |
71 | avpriv_set_pts_info(st, 64, 1, sample_rate); | |
72 | ||
73 | return res; | |
74 | ||
75 | fail: | |
76 | snd_pcm_close(s->h); | |
77 | return AVERROR(EIO); | |
78 | } | |
79 | ||
80 | static int audio_write_packet(AVFormatContext *s1, AVPacket *pkt) | |
81 | { | |
82 | AlsaData *s = s1->priv_data; | |
83 | int res; | |
84 | int size = pkt->size; | |
85 | uint8_t *buf = pkt->data; | |
86 | ||
87 | size /= s->frame_size; | |
88 | if (pkt->dts != AV_NOPTS_VALUE) | |
89 | s->timestamp = pkt->dts; | |
90 | s->timestamp += pkt->duration ? pkt->duration : size; | |
91 | ||
92 | if (s->reorder_func) { | |
93 | if (size > s->reorder_buf_size) | |
94 | if (ff_alsa_extend_reorder_buf(s, size)) | |
95 | return AVERROR(ENOMEM); | |
96 | s->reorder_func(buf, s->reorder_buf, size); | |
97 | buf = s->reorder_buf; | |
98 | } | |
99 | while ((res = snd_pcm_writei(s->h, buf, size)) < 0) { | |
100 | if (res == -EAGAIN) { | |
101 | ||
102 | return AVERROR(EAGAIN); | |
103 | } | |
104 | ||
105 | if (ff_alsa_xrun_recover(s1, res) < 0) { | |
106 | av_log(s1, AV_LOG_ERROR, "ALSA write error: %s\n", | |
107 | snd_strerror(res)); | |
108 | ||
109 | return AVERROR(EIO); | |
110 | } | |
111 | } | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | static int audio_write_frame(AVFormatContext *s1, int stream_index, | |
117 | AVFrame **frame, unsigned flags) | |
118 | { | |
119 | AlsaData *s = s1->priv_data; | |
120 | AVPacket pkt; | |
121 | ||
122 | /* ff_alsa_open() should have accepted only supported formats */ | |
123 | if ((flags & AV_WRITE_UNCODED_FRAME_QUERY)) | |
124 | return av_sample_fmt_is_planar(s1->streams[stream_index]->codec->sample_fmt) ? | |
125 | AVERROR(EINVAL) : 0; | |
126 | /* set only used fields */ | |
127 | pkt.data = (*frame)->data[0]; | |
128 | pkt.size = (*frame)->nb_samples * s->frame_size; | |
129 | pkt.dts = (*frame)->pkt_dts; | |
130 | pkt.duration = av_frame_get_pkt_duration(*frame); | |
131 | return audio_write_packet(s1, &pkt); | |
132 | } | |
133 | ||
134 | static void | |
135 | audio_get_output_timestamp(AVFormatContext *s1, int stream, | |
136 | int64_t *dts, int64_t *wall) | |
137 | { | |
138 | AlsaData *s = s1->priv_data; | |
139 | snd_pcm_sframes_t delay = 0; | |
140 | *wall = av_gettime(); | |
141 | snd_pcm_delay(s->h, &delay); | |
142 | *dts = s->timestamp - delay; | |
143 | } | |
144 | ||
f6fa7814 DM |
145 | static int audio_get_device_list(AVFormatContext *h, AVDeviceInfoList *device_list) |
146 | { | |
147 | return ff_alsa_get_device_list(device_list, SND_PCM_STREAM_PLAYBACK); | |
148 | } | |
149 | ||
2ba45a60 DM |
150 | static const AVClass alsa_muxer_class = { |
151 | .class_name = "ALSA muxer", | |
152 | .item_name = av_default_item_name, | |
153 | .version = LIBAVUTIL_VERSION_INT, | |
154 | .category = AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT, | |
155 | }; | |
156 | ||
157 | AVOutputFormat ff_alsa_muxer = { | |
158 | .name = "alsa", | |
159 | .long_name = NULL_IF_CONFIG_SMALL("ALSA audio output"), | |
160 | .priv_data_size = sizeof(AlsaData), | |
161 | .audio_codec = DEFAULT_CODEC_ID, | |
162 | .video_codec = AV_CODEC_ID_NONE, | |
163 | .write_header = audio_write_header, | |
164 | .write_packet = audio_write_packet, | |
165 | .write_trailer = ff_alsa_close, | |
166 | .write_uncoded_frame = audio_write_frame, | |
f6fa7814 | 167 | .get_device_list = audio_get_device_list, |
2ba45a60 DM |
168 | .get_output_timestamp = audio_get_output_timestamp, |
169 | .flags = AVFMT_NOFILE, | |
170 | .priv_class = &alsa_muxer_class, | |
171 | }; |