PeerStreamer

/*

 * 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: common code

 * @author Luca Abeni ( lucabe72 email it )

 * @author Benoit Fouet ( benoit fouet free fr )

 * @author Nicolas George ( nicolas george normalesup org )

 */

#include <alsa/asoundlib.h>

#include "libavformat/avformat.h"

#include "alsa-audio.h"

static av_cold snd_pcm_format_t codec_id_to_pcm_format(int codec_id)

{

    switch(codec_id) {

        case CODEC_ID_PCM_S16LE: return SND_PCM_FORMAT_S16_LE;

        case CODEC_ID_PCM_S16BE: return SND_PCM_FORMAT_S16_BE;

        case CODEC_ID_PCM_S8:    return SND_PCM_FORMAT_S8;

        default:                 return SND_PCM_FORMAT_UNKNOWN;

    }

}

static void alsa_reorder_s16_out_51(const void *in_v, void *out_v, int n)

{

    const int16_t *in = in_v;

    int16_t *out = out_v;

    while (n-- > 0) {

        out[0] = in[0];

        out[1] = in[1];

        out[2] = in[4];

        out[3] = in[5];

        out[4] = in[2];

        out[5] = in[3];

        in  += 6;

        out += 6;

    }

}

static void alsa_reorder_s16_out_71(const void *in_v, void *out_v, int n)

{

    const int16_t *in = in_v;

    int16_t *out = out_v;

    while (n-- > 0) {

        out[0] = in[0];

        out[1] = in[1];

        out[2] = in[4];

        out[3] = in[5];

        out[4] = in[2];

        out[5] = in[3];

        out[6] = in[6];

        out[7] = in[7];

        in  += 8;

        out += 8;

    }

}

#define REORDER_DUMMY ((void *)1)

static av_cold ff_reorder_func find_reorder_func(int codec_id,

                                                 int64_t layout,

                                                 int out)

{

    return

    codec_id == CODEC_ID_PCM_S16LE || codec_id == CODEC_ID_PCM_S16BE ?

        layout == AV_CH_LAYOUT_QUAD ? REORDER_DUMMY :

        layout == AV_CH_LAYOUT_5POINT1_BACK || layout == AV_CH_LAYOUT_5POINT1 ?

            out ? alsa_reorder_s16_out_51 : NULL :

        layout == AV_CH_LAYOUT_7POINT1 ?

            out ? alsa_reorder_s16_out_71 : NULL :

            NULL :

        NULL;

}

av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,

                         unsigned int *sample_rate,

                         int channels, enum CodecID *codec_id)

{

    AlsaData *s = ctx->priv_data;

    const char *audio_device;

    int res, flags = 0;

    snd_pcm_format_t format;

    snd_pcm_t *h;

    snd_pcm_hw_params_t *hw_params;

    snd_pcm_uframes_t buffer_size, period_size;

    int64_t layout = ctx->streams[0]->codec->channel_layout;

    if (ctx->filename[0] == 0) audio_device = "default";

    else                       audio_device = ctx->filename;

    if (*codec_id == CODEC_ID_NONE)

        *codec_id = DEFAULT_CODEC_ID;

    format = codec_id_to_pcm_format(*codec_id);

    if (format == SND_PCM_FORMAT_UNKNOWN) {

        av_log(ctx, AV_LOG_ERROR, "sample format 0x%04x is not supported\n", *codec_id);

        return AVERROR(ENOSYS);

    }

    s->frame_size = av_get_bits_per_sample(*codec_id) / 8 * channels;

    if (ctx->flags & AVFMT_FLAG_NONBLOCK) {

        flags = SND_PCM_NONBLOCK;

    }

    res = snd_pcm_open(&h, audio_device, mode, flags);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot open audio device %s (%s)\n",

               audio_device, snd_strerror(res));

        return AVERROR(EIO);

    }

    res = snd_pcm_hw_params_malloc(&hw_params);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot allocate hardware parameter structure (%s)\n",

               snd_strerror(res));

        goto fail1;

    }

    res = snd_pcm_hw_params_any(h, hw_params);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot initialize hardware parameter structure (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    res = snd_pcm_hw_params_set_access(h, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set access type (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    res = snd_pcm_hw_params_set_format(h, hw_params, format);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set sample format 0x%04x %d (%s)\n",

               *codec_id, format, snd_strerror(res));

        goto fail;

    }

    res = snd_pcm_hw_params_set_rate_near(h, hw_params, sample_rate, 0);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set sample rate (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    res = snd_pcm_hw_params_set_channels(h, hw_params, channels);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set channel count to %d (%s)\n",

               channels, snd_strerror(res));

        goto fail;

    }

    snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size);

    /* TODO: maybe use ctx->max_picture_buffer somehow */

    res = snd_pcm_hw_params_set_buffer_size_near(h, hw_params, &buffer_size);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set ALSA buffer size (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    snd_pcm_hw_params_get_period_size_min(hw_params, &period_size, NULL);

    res = snd_pcm_hw_params_set_period_size_near(h, hw_params, &period_size, NULL);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set ALSA period size (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    s->period_size = period_size;

    res = snd_pcm_hw_params(h, hw_params);

    if (res < 0) {

        av_log(ctx, AV_LOG_ERROR, "cannot set parameters (%s)\n",

               snd_strerror(res));

        goto fail;

    }

    snd_pcm_hw_params_free(hw_params);

    if (channels > 2 && layout) {

        s->reorder_func = find_reorder_func(*codec_id, layout,

                                            mode == SND_PCM_STREAM_PLAYBACK);

        if (s->reorder_func == REORDER_DUMMY) {

            s->reorder_func = NULL;

        } else if (s->reorder_func) {

            s->reorder_buf_size = buffer_size;

            s->reorder_buf = av_malloc(s->reorder_buf_size * s->frame_size);

            if (!s->reorder_buf)

                goto fail1;

        } else {

            char name[16];

            av_get_channel_layout_string(name, sizeof(name), channels, layout);

            av_log(ctx, AV_LOG_WARNING,

                   "ALSA channel layout unknown or unimplemented for %s %s.\n",

                   name,

                   mode == SND_PCM_STREAM_PLAYBACK ? "playback" : "capture");

        }

    }

    s->h = h;

    return 0;

fail:

    snd_pcm_hw_params_free(hw_params);

fail1:

    snd_pcm_close(h);

    return AVERROR(EIO);

}

av_cold int ff_alsa_close(AVFormatContext *s1)

{

    AlsaData *s = s1->priv_data;

    av_freep(&s->reorder_buf);

    snd_pcm_close(s->h);

    return 0;

}

int ff_alsa_xrun_recover(AVFormatContext *s1, int err)

{

    AlsaData *s = s1->priv_data;

    snd_pcm_t *handle = s->h;

    av_log(s1, AV_LOG_WARNING, "ALSA buffer xrun.\n");

    if (err == -EPIPE) {

        err = snd_pcm_prepare(handle);

        if (err < 0) {

            av_log(s1, AV_LOG_ERROR, "cannot recover from underrun (snd_pcm_prepare failed: %s)\n", snd_strerror(err));

            return AVERROR(EIO);

        }

    } else if (err == -ESTRPIPE) {

        av_log(s1, AV_LOG_ERROR, "-ESTRPIPE... Unsupported!\n");

        return -1;

    }

    return err;

}

int ff_alsa_extend_reorder_buf(AlsaData *s, int min_size)

{

    int size = s->reorder_buf_size;

    void *r;

    while (size < min_size)

        size *= 2;

    r = av_realloc(s->reorder_buf, size * s->frame_size);

    if (!r)

        return AVERROR(ENOMEM);

    s->reorder_buf = r;

    s->reorder_buf_size = size;

    return 0;

}