yading@10: /*
yading@10:  * Copyright (c) 2011 Jonathan Baldwin
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * Permission to use, copy, modify, and/or distribute this software for any
yading@10:  * purpose with or without fee is hereby granted, provided that the above
yading@10:  * copyright notice and this permission notice appear in all copies.
yading@10:  *
yading@10:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
yading@10:  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
yading@10:  * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
yading@10:  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
yading@10:  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
yading@10:  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
yading@10:  * PERFORMANCE OF THIS SOFTWARE.
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * OpenAL 1.1 capture device for libavdevice
yading@10:  **/
yading@10: 
yading@10: #include <AL/al.h>
yading@10: #include <AL/alc.h>
yading@10: 
yading@10: #include "libavutil/opt.h"
yading@10: #include "libavutil/time.h"
yading@10: #include "libavformat/internal.h"
yading@10: #include "avdevice.h"
yading@10: 
yading@10: typedef struct {
yading@10:     AVClass *class;
yading@10:     /** OpenAL capture device context. **/
yading@10:     ALCdevice *device;
yading@10:     /** The number of channels in the captured audio. **/
yading@10:     int channels;
yading@10:     /** The sample rate (in Hz) of the captured audio. **/
yading@10:     int sample_rate;
yading@10:     /** The sample size (in bits) of the captured audio. **/
yading@10:     int sample_size;
yading@10:     /** The OpenAL sample format of the captured audio. **/
yading@10:     ALCenum sample_format;
yading@10:     /** The number of bytes between two consecutive samples of the same channel/component. **/
yading@10:     ALCint sample_step;
yading@10:     /** If true, print a list of capture devices on this system and exit. **/
yading@10:     int list_devices;
yading@10: } al_data;
yading@10: 
yading@10: typedef struct {
yading@10:     ALCenum al_fmt;
yading@10:     enum AVCodecID codec_id;
yading@10:     int channels;
yading@10: } al_format_info;
yading@10: 
yading@10: #define LOWEST_AL_FORMAT FFMIN(FFMIN(AL_FORMAT_MONO8,AL_FORMAT_MONO16),FFMIN(AL_FORMAT_STEREO8,AL_FORMAT_STEREO16))
yading@10: 
yading@10: /**
yading@10:  * Get information about an AL_FORMAT value.
yading@10:  * @param al_fmt the AL_FORMAT value to find information about.
yading@10:  * @return A pointer to a structure containing information about the AL_FORMAT value.
yading@10:  */
yading@10: static inline al_format_info* get_al_format_info(ALCenum al_fmt)
yading@10: {
yading@10:     static al_format_info info_table[] = {
yading@10:         [AL_FORMAT_MONO8-LOWEST_AL_FORMAT]    = {AL_FORMAT_MONO8, AV_CODEC_ID_PCM_U8, 1},
yading@10:         [AL_FORMAT_MONO16-LOWEST_AL_FORMAT]   = {AL_FORMAT_MONO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 1},
yading@10:         [AL_FORMAT_STEREO8-LOWEST_AL_FORMAT]  = {AL_FORMAT_STEREO8, AV_CODEC_ID_PCM_U8, 2},
yading@10:         [AL_FORMAT_STEREO16-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 2},
yading@10:     };
yading@10: 
yading@10:     return &info_table[al_fmt-LOWEST_AL_FORMAT];
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Get the OpenAL error code, translated into an av/errno error code.
yading@10:  * @param device The ALC device to check for errors.
yading@10:  * @param error_msg_ret A pointer to a char* in which to return the error message, or NULL if desired.
yading@10:  * @return The error code, or 0 if there is no error.
yading@10:  */
yading@10: static inline int al_get_error(ALCdevice *device, const char** error_msg_ret)
yading@10: {
yading@10:     ALCenum error = alcGetError(device);
yading@10:     if (error_msg_ret)
yading@10:         *error_msg_ret = (const char*) alcGetString(device, error);
yading@10:     switch (error) {
yading@10:     case ALC_NO_ERROR:
yading@10:         return 0;
yading@10:     case ALC_INVALID_DEVICE:
yading@10:         return AVERROR(ENODEV);
yading@10:         break;
yading@10:     case ALC_INVALID_CONTEXT:
yading@10:     case ALC_INVALID_ENUM:
yading@10:     case ALC_INVALID_VALUE:
yading@10:         return AVERROR(EINVAL);
yading@10:         break;
yading@10:     case ALC_OUT_OF_MEMORY:
yading@10:         return AVERROR(ENOMEM);
yading@10:         break;
yading@10:     default:
yading@10:         return AVERROR(EIO);
yading@10:     }
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Print out a list of OpenAL capture devices on this system.
yading@10:  */
yading@10: static inline void print_al_capture_devices(void *log_ctx)
yading@10: {
yading@10:     const char *devices;
yading@10: 
yading@10:     if (!(devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER)))
yading@10:         return;
yading@10: 
yading@10:     av_log(log_ctx, AV_LOG_INFO, "List of OpenAL capture devices on this system:\n");
yading@10: 
yading@10:     for (; *devices != '\0'; devices += strlen(devices) + 1)
yading@10:         av_log(log_ctx, AV_LOG_INFO, "  %s\n", devices);
yading@10: }
yading@10: 
yading@10: static int read_header(AVFormatContext *ctx)
yading@10: {
yading@10:     al_data *ad = ctx->priv_data;
yading@10:     static const ALCenum sample_formats[2][2] = {
yading@10:         { AL_FORMAT_MONO8,  AL_FORMAT_STEREO8  },
yading@10:         { AL_FORMAT_MONO16, AL_FORMAT_STEREO16 }
yading@10:     };
yading@10:     int error = 0;
yading@10:     const char *error_msg;
yading@10:     AVStream *st = NULL;
yading@10:     AVCodecContext *codec = NULL;
yading@10: 
yading@10:     if (ad->list_devices) {
yading@10:         print_al_capture_devices(ctx);
yading@10:         return AVERROR_EXIT;
yading@10:     }
yading@10: 
yading@10:     ad->sample_format = sample_formats[ad->sample_size/8-1][ad->channels-1];
yading@10: 
yading@10:     /* Open device for capture */
yading@10:     ad->device =
yading@10:         alcCaptureOpenDevice(ctx->filename[0] ? ctx->filename : NULL,
yading@10:                              ad->sample_rate,
yading@10:                              ad->sample_format,
yading@10:                              ad->sample_rate); /* Maximum 1 second of sample data to be read at once */
yading@10: 
yading@10:     if (error = al_get_error(ad->device, &error_msg)) goto fail;
yading@10: 
yading@10:     /* Create stream */
yading@10:     if (!(st = avformat_new_stream(ctx, NULL))) {
yading@10:         error = AVERROR(ENOMEM);
yading@10:         goto fail;
yading@10:     }
yading@10: 
yading@10:     /* We work in microseconds */
yading@10:     avpriv_set_pts_info(st, 64, 1, 1000000);
yading@10: 
yading@10:     /* Set codec parameters */
yading@10:     codec = st->codec;
yading@10:     codec->codec_type = AVMEDIA_TYPE_AUDIO;
yading@10:     codec->sample_rate = ad->sample_rate;
yading@10:     codec->channels = get_al_format_info(ad->sample_format)->channels;
yading@10:     codec->codec_id = get_al_format_info(ad->sample_format)->codec_id;
yading@10: 
yading@10:     /* This is needed to read the audio data */
yading@10:     ad->sample_step = (av_get_bits_per_sample(get_al_format_info(ad->sample_format)->codec_id) *
yading@10:                        get_al_format_info(ad->sample_format)->channels) / 8;
yading@10: 
yading@10:     /* Finally, start the capture process */
yading@10:     alcCaptureStart(ad->device);
yading@10: 
yading@10:     return 0;
yading@10: 
yading@10: fail:
yading@10:     /* Handle failure */
yading@10:     if (ad->device)
yading@10:         alcCaptureCloseDevice(ad->device);
yading@10:     if (error_msg)
yading@10:         av_log(ctx, AV_LOG_ERROR, "Cannot open device: %s\n", error_msg);
yading@10:     return error;
yading@10: }
yading@10: 
yading@10: static int read_packet(AVFormatContext* ctx, AVPacket *pkt)
yading@10: {
yading@10:     al_data *ad = ctx->priv_data;
yading@10:     int error=0;
yading@10:     const char *error_msg;
yading@10:     ALCint nb_samples;
yading@10: 
yading@10:     /* Get number of samples available */
yading@10:     alcGetIntegerv(ad->device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &nb_samples);
yading@10:     if (error = al_get_error(ad->device, &error_msg)) goto fail;
yading@10: 
yading@10:     /* Create a packet of appropriate size */
yading@10:     av_new_packet(pkt, nb_samples*ad->sample_step);
yading@10:     pkt->pts = av_gettime();
yading@10: 
yading@10:     /* Fill the packet with the available samples */
yading@10:     alcCaptureSamples(ad->device, pkt->data, nb_samples);
yading@10:     if (error = al_get_error(ad->device, &error_msg)) goto fail;
yading@10: 
yading@10:     return pkt->size;
yading@10: fail:
yading@10:     /* Handle failure */
yading@10:     if (pkt->data)
yading@10:         av_destruct_packet(pkt);
yading@10:     if (error_msg)
yading@10:         av_log(ctx, AV_LOG_ERROR, "Error: %s\n", error_msg);
yading@10:     return error;
yading@10: }
yading@10: 
yading@10: static int read_close(AVFormatContext* ctx)
yading@10: {
yading@10:     al_data *ad = ctx->priv_data;
yading@10: 
yading@10:     if (ad->device) {
yading@10:         alcCaptureStop(ad->device);
yading@10:         alcCaptureCloseDevice(ad->device);
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: #define OFFSET(x) offsetof(al_data, x)
yading@10: 
yading@10: static const AVOption options[] = {
yading@10:     {"channels", "set number of channels",     OFFSET(channels),     AV_OPT_TYPE_INT, {.i64=2},     1, 2,      AV_OPT_FLAG_DECODING_PARAM },
yading@10:     {"sample_rate", "set sample rate",         OFFSET(sample_rate),  AV_OPT_TYPE_INT, {.i64=44100}, 1, 192000, AV_OPT_FLAG_DECODING_PARAM },
yading@10:     {"sample_size", "set sample size",         OFFSET(sample_size),  AV_OPT_TYPE_INT, {.i64=16},    8, 16,     AV_OPT_FLAG_DECODING_PARAM },
yading@10:     {"list_devices", "list available devices", OFFSET(list_devices), AV_OPT_TYPE_INT, {.i64=0},     0, 1,      AV_OPT_FLAG_DECODING_PARAM, "list_devices"  },
yading@10:     {"true",  "", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
yading@10:     {"false", "", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
yading@10:     {NULL},
yading@10: };
yading@10: 
yading@10: static const AVClass class = {
yading@10:     .class_name = "openal",
yading@10:     .item_name = av_default_item_name,
yading@10:     .option = options,
yading@10:     .version = LIBAVUTIL_VERSION_INT
yading@10: };
yading@10: 
yading@10: AVInputFormat ff_openal_demuxer = {
yading@10:     .name = "openal",
yading@10:     .long_name = NULL_IF_CONFIG_SMALL("OpenAL audio capture device"),
yading@10:     .priv_data_size = sizeof(al_data),
yading@10:     .read_probe = NULL,
yading@10:     .read_header = read_header,
yading@10:     .read_packet = read_packet,
yading@10:     .read_close = read_close,
yading@10:     .flags = AVFMT_NOFILE,
yading@10:     .priv_class = &class
yading@10: };