audio.c

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/*
 * Copyright (c) Stefano Sabatini | stefasab at gmail.com
 * Copyright (c) S.N. Hemanth Meenakshisundaram | smeenaks at ucsd.edu
 *
 * 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
 */
 
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "libavutil/cpu.h"
#include "libavutil/eval.h"
 
#include "audio.h"
#include "avfilter.h"
#include "avfilter_internal.h"
#include "filters.h"
#include "framepool.h"
 
const AVFilterPad ff_audio_default_filterpad[1] = {
    {
        .name = "default",
        .type = AVMEDIA_TYPE_AUDIO,
    }
};
 
AVFrame *ff_null_get_audio_buffer(AVFilterLink *link, int nb_samples)
{
    return ff_get_audio_buffer(link->dst->outputs[0], nb_samples);
}
 
AVFrame *ff_default_get_audio_buffer(AVFilterLink *link, int nb_samples)
{
    AVFrame *frame = NULL;
    FilterLinkInternal *const li = ff_link_internal(link);
    int channels = link->ch_layout.nb_channels;
    int align = av_cpu_max_align();
 
    if (ff_frame_pool_audio_reinit(&li->frame_pool, channels, nb_samples,
                                   link->format, align) < 0)
        return NULL;
 
    frame = ff_frame_pool_get(&li->frame_pool);
    if (!frame)
        return NULL;
 
    frame->nb_samples = nb_samples;
    if (link->ch_layout.order != AV_CHANNEL_ORDER_UNSPEC &&
        av_channel_layout_copy(&frame->ch_layout, &link->ch_layout) < 0) {
        av_frame_free(&frame);
        return NULL;
    }
    frame->sample_rate = link->sample_rate;
 
    av_samples_set_silence(frame->extended_data, 0, nb_samples, channels, link->format);
 
    return frame;
}
 
AVFrame *ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
{
    AVFrame *ret = NULL;
 
    if (link->dstpad->get_buffer.audio)
        ret = link->dstpad->get_buffer.audio(link, nb_samples);
 
    if (!ret)
        ret = ff_default_get_audio_buffer(link, nb_samples);
 
    return ret;
}
 
int ff_parse_sample_rate(int *ret, const char *arg, void *log_ctx)
{
    char *tail;
    double srate = av_strtod(arg, &tail);
    if (*tail || srate < 1 || (int)srate != srate || srate > INT_MAX) {
        av_log(log_ctx, AV_LOG_ERROR, "Invalid sample rate '%s'\n", arg);
        return AVERROR(EINVAL);
    }
    *ret = srate;
    return 0;
}
 
int ff_parse_channel_layout(AVChannelLayout *ret, int *nret, const char *arg,
                            void *log_ctx)
{
    AVChannelLayout chlayout = { 0 };
    int res;
 
    res = av_channel_layout_from_string(&chlayout, arg);
    if (res < 0) {
        av_log(log_ctx, AV_LOG_ERROR, "Invalid channel layout '%s'\n", arg);
        return AVERROR(EINVAL);
    }
 
    if (chlayout.order == AV_CHANNEL_ORDER_UNSPEC && !nret) {
        av_log(log_ctx, AV_LOG_ERROR, "Unknown channel layout '%s' is not supported.\n", arg);
        return AVERROR(EINVAL);
    }
    *ret = chlayout;
    if (nret)
        *nret = chlayout.nb_channels;
 
    return 0;
}