/* * Copyright (c) 2012 Andrey Utkin * Copyright (c) 2012 Stefano Sabatini * * 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 * Filter that changes number of samples on single output operation */ #include "libavutil/audio_fifo.h"#include "libavutil/avassert.h"#include "libavutil/channel_layout.h"#include "libavutil/opt.h"#include "avfilter.h"#include "audio.h"#include "internal.h"#include "formats.h" typedef struct ASNSContext {    const AVClass *class;    int nb_out_samples;  ///< how many samples to output    AVAudioFifo *fifo;   ///< samples are queued here    int64_t next_out_pts;    int pad;} ASNSContext; #define OFFSET(x) offsetof(ASNSContext, x)#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM static const AVOption asetnsamples_options[] = {    { "nb_out_samples", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },    { "n",              "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },    { "pad", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },    { "p",   "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },    { NULL }}; AVFILTER_DEFINE_CLASS(asetnsamples); static av_cold int init(AVFilterContext *ctx){    ASNSContext *asns = ctx->priv;     asns->next_out_pts = AV_NOPTS_VALUE;    av_log(ctx, AV_LOG_VERBOSE, "nb_out_samples:%d pad:%d\n", asns->nb_out_samples, asns->pad);     return 0;} static av_cold void uninit(AVFilterContext *ctx){    ASNSContext *asns = ctx->priv;    av_audio_fifo_free(asns->fifo);} static int config_props_output(AVFilterLink *outlink){    ASNSContext *asns = outlink->src->priv;     asns->fifo = av_audio_fifo_alloc(outlink->format, outlink->channels, asns->nb_out_samples);    if (!asns->fifo)        return AVERROR(ENOMEM);     return 0;} static int push_samples(AVFilterLink *outlink){    ASNSContext *asns = outlink->src->priv;    AVFrame *outsamples = NULL;    int ret, nb_out_samples, nb_pad_samples;     if (asns->pad) {        nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0;        nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo));    } else {        nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));        nb_pad_samples = 0;    }     if (!nb_out_samples)        return 0;     outsamples = ff_get_audio_buffer(outlink, nb_out_samples);    if (!outsamples)        return AVERROR(ENOMEM);     av_audio_fifo_read(asns->fifo,                       (void **)outsamples->extended_data, nb_out_samples);     if (nb_pad_samples)        av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,                               nb_pad_samples, outlink->channels,                               outlink->format);    outsamples->nb_samples     = nb_out_samples;    outsamples->channel_layout = outlink->channel_layout;    outsamples->sample_rate    = outlink->sample_rate;    outsamples->pts = asns->next_out_pts;     if (asns->next_out_pts != AV_NOPTS_VALUE)        asns->next_out_pts += av_rescale_q(nb_out_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);     ret = ff_filter_frame(outlink, outsamples);    if (ret < 0)        return ret;    return nb_out_samples;} static int filter_frame(AVFilterLink *inlink, AVFrame *insamples){    AVFilterContext *ctx = inlink->dst;    ASNSContext *asns = ctx->priv;    AVFilterLink *outlink = ctx->outputs[0];    int ret;    int nb_samples = insamples->nb_samples;     if (av_audio_fifo_space(asns->fifo) < nb_samples) {        av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples);        ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples);        if (ret < 0) {            av_log(ctx, AV_LOG_ERROR,                   "Stretching audio fifo failed, discarded %d samples\n", nb_samples);            return -1;        }    }    av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);    if (asns->next_out_pts == AV_NOPTS_VALUE)        asns->next_out_pts = insamples->pts;    av_frame_free(&insamples);     while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)        push_samples(outlink);    return 0;} static int request_frame(AVFilterLink *outlink){    AVFilterLink *inlink = outlink->src->inputs[0];    int ret;     ret = ff_request_frame(inlink);    if (ret == AVERROR_EOF) {        ret = push_samples(outlink);        return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF;    }     return ret;} static const AVFilterPad asetnsamples_inputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_AUDIO,        .filter_frame = filter_frame,    },    { NULL }}; static const AVFilterPad asetnsamples_outputs[] = {    {        .name          = "default",        .type          = AVMEDIA_TYPE_AUDIO,        .request_frame = request_frame,        .config_props  = config_props_output,    },    { NULL }}; AVFilter ff_af_asetnsamples = {    .name        = "asetnsamples",    .description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."),    .priv_size   = sizeof(ASNSContext),    .priv_class  = &asetnsamples_class,    .init        = init,    .uninit      = uninit,    .inputs      = asetnsamples_inputs,    .outputs     = asetnsamples_outputs,};