262 lines
8.5 KiB
C
262 lines
8.5 KiB
C
/*
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* Copyright (c) 2011 Jonathan Baldwin
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*
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* This file is part of FFmpeg.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/**
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* @file
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* OpenAL 1.1 capture device for libavdevice
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**/
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#include <AL/al.h>
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#include <AL/alc.h>
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#include "libavutil/opt.h"
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#include "libavutil/time.h"
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#include "libavformat/internal.h"
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#include "avdevice.h"
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typedef struct {
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AVClass *class;
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/** OpenAL capture device context. **/
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ALCdevice *device;
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/** The number of channels in the captured audio. **/
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int channels;
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/** The sample rate (in Hz) of the captured audio. **/
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int sample_rate;
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/** The sample size (in bits) of the captured audio. **/
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int sample_size;
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/** The OpenAL sample format of the captured audio. **/
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ALCenum sample_format;
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/** The number of bytes between two consecutive samples of the same channel/component. **/
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ALCint sample_step;
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/** If true, print a list of capture devices on this system and exit. **/
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int list_devices;
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} al_data;
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typedef struct {
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ALCenum al_fmt;
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enum AVCodecID codec_id;
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int channels;
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} al_format_info;
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#define LOWEST_AL_FORMAT FFMIN(FFMIN(AL_FORMAT_MONO8,AL_FORMAT_MONO16),FFMIN(AL_FORMAT_STEREO8,AL_FORMAT_STEREO16))
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/**
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* Get information about an AL_FORMAT value.
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* @param al_fmt the AL_FORMAT value to find information about.
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* @return A pointer to a structure containing information about the AL_FORMAT value.
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*/
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static const inline al_format_info* get_al_format_info(ALCenum al_fmt)
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{
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static const al_format_info info_table[] = {
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[AL_FORMAT_MONO8-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO8, AV_CODEC_ID_PCM_U8, 1},
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[AL_FORMAT_MONO16-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 1},
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[AL_FORMAT_STEREO8-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO8, AV_CODEC_ID_PCM_U8, 2},
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[AL_FORMAT_STEREO16-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 2},
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};
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return &info_table[al_fmt-LOWEST_AL_FORMAT];
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}
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/**
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* Get the OpenAL error code, translated into an av/errno error code.
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* @param device The ALC device to check for errors.
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* @param error_msg_ret A pointer to a char* in which to return the error message, or NULL if desired.
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* @return The error code, or 0 if there is no error.
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*/
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static inline int al_get_error(ALCdevice *device, const char** error_msg_ret)
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{
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ALCenum error = alcGetError(device);
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if (error_msg_ret)
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*error_msg_ret = (const char*) alcGetString(device, error);
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switch (error) {
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case ALC_NO_ERROR:
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return 0;
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case ALC_INVALID_DEVICE:
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return AVERROR(ENODEV);
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break;
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case ALC_INVALID_CONTEXT:
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case ALC_INVALID_ENUM:
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case ALC_INVALID_VALUE:
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return AVERROR(EINVAL);
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break;
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case ALC_OUT_OF_MEMORY:
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return AVERROR(ENOMEM);
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break;
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default:
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return AVERROR(EIO);
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}
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}
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/**
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* Print out a list of OpenAL capture devices on this system.
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*/
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static inline void print_al_capture_devices(void *log_ctx)
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{
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const char *devices;
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if (!(devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER)))
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return;
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av_log(log_ctx, AV_LOG_INFO, "List of OpenAL capture devices on this system:\n");
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for (; *devices != '\0'; devices += strlen(devices) + 1)
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av_log(log_ctx, AV_LOG_INFO, " %s\n", devices);
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}
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static int read_header(AVFormatContext *ctx)
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{
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al_data *ad = ctx->priv_data;
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static const ALCenum sample_formats[2][2] = {
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{ AL_FORMAT_MONO8, AL_FORMAT_STEREO8 },
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{ AL_FORMAT_MONO16, AL_FORMAT_STEREO16 }
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};
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int error = 0;
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const char *error_msg;
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AVStream *st = NULL;
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AVCodecParameters *par = NULL;
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if (ad->list_devices) {
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print_al_capture_devices(ctx);
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return AVERROR_EXIT;
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}
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ad->sample_format = sample_formats[ad->sample_size/8-1][ad->channels-1];
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/* Open device for capture */
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ad->device =
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alcCaptureOpenDevice(ctx->url[0] ? ctx->url : NULL,
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ad->sample_rate,
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ad->sample_format,
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ad->sample_rate); /* Maximum 1 second of sample data to be read at once */
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if (error = al_get_error(ad->device, &error_msg)) goto fail;
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/* Create stream */
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if (!(st = avformat_new_stream(ctx, NULL))) {
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error = AVERROR(ENOMEM);
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goto fail;
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}
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/* We work in microseconds */
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avpriv_set_pts_info(st, 64, 1, 1000000);
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/* Set codec parameters */
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par = st->codecpar;
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par->codec_type = AVMEDIA_TYPE_AUDIO;
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par->sample_rate = ad->sample_rate;
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par->channels = get_al_format_info(ad->sample_format)->channels;
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par->codec_id = get_al_format_info(ad->sample_format)->codec_id;
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/* This is needed to read the audio data */
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ad->sample_step = (av_get_bits_per_sample(get_al_format_info(ad->sample_format)->codec_id) *
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get_al_format_info(ad->sample_format)->channels) / 8;
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/* Finally, start the capture process */
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alcCaptureStart(ad->device);
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return 0;
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fail:
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/* Handle failure */
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if (ad->device)
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alcCaptureCloseDevice(ad->device);
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if (error_msg)
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av_log(ctx, AV_LOG_ERROR, "Cannot open device: %s\n", error_msg);
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return error;
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}
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static int read_packet(AVFormatContext* ctx, AVPacket *pkt)
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{
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al_data *ad = ctx->priv_data;
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int error=0;
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const char *error_msg;
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ALCint nb_samples;
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for (;;) {
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/* Get number of samples available */
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alcGetIntegerv(ad->device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &nb_samples);
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if (error = al_get_error(ad->device, &error_msg)) goto fail;
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if (nb_samples > 0)
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break;
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if (ctx->flags & AVFMT_FLAG_NONBLOCK)
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return AVERROR(EAGAIN);
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av_usleep(1000);
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}
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/* Create a packet of appropriate size */
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if ((error = av_new_packet(pkt, nb_samples*ad->sample_step)) < 0)
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goto fail;
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pkt->pts = av_gettime();
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/* Fill the packet with the available samples */
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alcCaptureSamples(ad->device, pkt->data, nb_samples);
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if (error = al_get_error(ad->device, &error_msg)) goto fail;
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return pkt->size;
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fail:
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/* Handle failure */
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if (pkt->data)
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av_packet_unref(pkt);
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if (error_msg)
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av_log(ctx, AV_LOG_ERROR, "Error: %s\n", error_msg);
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return error;
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}
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static int read_close(AVFormatContext* ctx)
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{
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al_data *ad = ctx->priv_data;
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if (ad->device) {
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alcCaptureStop(ad->device);
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alcCaptureCloseDevice(ad->device);
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}
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return 0;
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}
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#define OFFSET(x) offsetof(al_data, x)
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static const AVOption options[] = {
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{"channels", "set number of channels", OFFSET(channels), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, AV_OPT_FLAG_DECODING_PARAM },
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{"sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, 192000, AV_OPT_FLAG_DECODING_PARAM },
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{"sample_size", "set sample size", OFFSET(sample_size), AV_OPT_TYPE_INT, {.i64=16}, 8, 16, AV_OPT_FLAG_DECODING_PARAM },
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{"list_devices", "list available devices", OFFSET(list_devices), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
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{"true", "", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
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{"false", "", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
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{NULL},
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};
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static const AVClass class = {
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.class_name = "openal",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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.category = AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
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};
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AVInputFormat ff_openal_demuxer = {
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.name = "openal",
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.long_name = NULL_IF_CONFIG_SMALL("OpenAL audio capture device"),
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.priv_data_size = sizeof(al_data),
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.read_probe = NULL,
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.read_header = read_header,
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.read_packet = read_packet,
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.read_close = read_close,
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.flags = AVFMT_NOFILE,
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.priv_class = &class
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};
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