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 libavdevice/alsa-audio-common.c
25 * ALSA input and output: common code
26 * @author Luca Abeni ( lucabe72 email it )
27 * @author Benoit Fouet ( benoit fouet free fr )
28 * @author Nicolas George ( nicolas george normalesup org )
29 */
30
31#include "libavformat/avformat.h"
32#include <alsa/asoundlib.h>
33
34#include "alsa-audio.h"
35
36static av_cold snd_pcm_format_t codec_id_to_pcm_format(int codec_id)
37{
38    switch(codec_id) {
39        case CODEC_ID_PCM_S16LE: return SND_PCM_FORMAT_S16_LE;
40        case CODEC_ID_PCM_S16BE: return SND_PCM_FORMAT_S16_BE;
41        case CODEC_ID_PCM_S8:    return SND_PCM_FORMAT_S8;
42        default:                 return SND_PCM_FORMAT_UNKNOWN;
43    }
44}
45
46av_cold int ff_alsa_open(AVFormatContext *ctx, int mode,
47                         unsigned int *sample_rate,
48                         int channels, int *codec_id)
49{
50    AlsaData *s = ctx->priv_data;
51    const char *audio_device;
52    int res, flags = 0;
53    snd_pcm_format_t format;
54    snd_pcm_t *h;
55    snd_pcm_hw_params_t *hw_params;
56    snd_pcm_uframes_t buffer_size, period_size;
57
58    if (ctx->filename[0] == 0) audio_device = "default";
59    else                       audio_device = ctx->filename;
60
61    if (*codec_id == CODEC_ID_NONE)
62        *codec_id = DEFAULT_CODEC_ID;
63    format = codec_id_to_pcm_format(*codec_id);
64    if (format == SND_PCM_FORMAT_UNKNOWN) {
65        av_log(ctx, AV_LOG_ERROR, "sample format 0x%04x is not supported\n", *codec_id);
66        return AVERROR(ENOSYS);
67    }
68    s->frame_size = av_get_bits_per_sample(*codec_id) / 8 * channels;
69
70    if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
71        flags = O_NONBLOCK;
72    }
73    res = snd_pcm_open(&h, audio_device, mode, flags);
74    if (res < 0) {
75        av_log(ctx, AV_LOG_ERROR, "cannot open audio device %s (%s)\n",
76               audio_device, snd_strerror(res));
77        return AVERROR_IO;
78    }
79
80    res = snd_pcm_hw_params_malloc(&hw_params);
81    if (res < 0) {
82        av_log(ctx, AV_LOG_ERROR, "cannot allocate hardware parameter structure (%s)\n",
83               snd_strerror(res));
84        goto fail1;
85    }
86
87    res = snd_pcm_hw_params_any(h, hw_params);
88    if (res < 0) {
89        av_log(ctx, AV_LOG_ERROR, "cannot initialize hardware parameter structure (%s)\n",
90               snd_strerror(res));
91        goto fail;
92    }
93
94    res = snd_pcm_hw_params_set_access(h, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
95    if (res < 0) {
96        av_log(ctx, AV_LOG_ERROR, "cannot set access type (%s)\n",
97               snd_strerror(res));
98        goto fail;
99    }
100
101    res = snd_pcm_hw_params_set_format(h, hw_params, format);
102    if (res < 0) {
103        av_log(ctx, AV_LOG_ERROR, "cannot set sample format 0x%04x %d (%s)\n",
104               *codec_id, format, snd_strerror(res));
105        goto fail;
106    }
107
108    res = snd_pcm_hw_params_set_rate_near(h, hw_params, sample_rate, 0);
109    if (res < 0) {
110        av_log(ctx, AV_LOG_ERROR, "cannot set sample rate (%s)\n",
111               snd_strerror(res));
112        goto fail;
113    }
114
115    res = snd_pcm_hw_params_set_channels(h, hw_params, channels);
116    if (res < 0) {
117        av_log(ctx, AV_LOG_ERROR, "cannot set channel count to %d (%s)\n",
118               channels, snd_strerror(res));
119        goto fail;
120    }
121
122    snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size);
123    /* TODO: maybe use ctx->max_picture_buffer somehow */
124    res = snd_pcm_hw_params_set_buffer_size_near(h, hw_params, &buffer_size);
125    if (res < 0) {
126        av_log(ctx, AV_LOG_ERROR, "cannot set ALSA buffer size (%s)\n",
127               snd_strerror(res));
128        goto fail;
129    }
130
131    snd_pcm_hw_params_get_period_size_min(hw_params, &period_size, NULL);
132    res = snd_pcm_hw_params_set_period_size_near(h, hw_params, &period_size, NULL);
133    if (res < 0) {
134        av_log(ctx, AV_LOG_ERROR, "cannot set ALSA period size (%s)\n",
135               snd_strerror(res));
136        goto fail;
137    }
138    s->period_size = period_size;
139
140    res = snd_pcm_hw_params(h, hw_params);
141    if (res < 0) {
142        av_log(ctx, AV_LOG_ERROR, "cannot set parameters (%s)\n",
143               snd_strerror(res));
144        goto fail;
145    }
146
147    snd_pcm_hw_params_free(hw_params);
148
149    s->h = h;
150    return 0;
151
152fail:
153    snd_pcm_hw_params_free(hw_params);
154fail1:
155    snd_pcm_close(h);
156    return AVERROR_IO;
157}
158
159av_cold int ff_alsa_close(AVFormatContext *s1)
160{
161    AlsaData *s = s1->priv_data;
162
163    snd_pcm_close(s->h);
164    return 0;
165}
166
167int ff_alsa_xrun_recover(AVFormatContext *s1, int err)
168{
169    AlsaData *s = s1->priv_data;
170    snd_pcm_t *handle = s->h;
171
172    av_log(s1, AV_LOG_WARNING, "ALSA buffer xrun.\n");
173    if (err == -EPIPE) {
174        err = snd_pcm_prepare(handle);
175        if (err < 0) {
176            av_log(s1, AV_LOG_ERROR, "cannot recover from underrun (snd_pcm_prepare failed: %s)\n", snd_strerror(err));
177
178            return AVERROR_IO;
179        }
180    } else if (err == -ESTRPIPE) {
181        av_log(s1, AV_LOG_ERROR, "-ESTRPIPE... Unsupported!\n");
182
183        return -1;
184    }
185    return err;
186}
187