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