yading@10: /*
yading@10:  * Copyright (c) 2012 Andrey Utkin
yading@10:  * Copyright (c) 2012 Stefano Sabatini
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Filter that changes number of samples on single output operation
yading@10:  */
yading@10: 
yading@10: #include "libavutil/audio_fifo.h"
yading@10: #include "libavutil/avassert.h"
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/opt.h"
yading@10: #include "avfilter.h"
yading@10: #include "audio.h"
yading@10: #include "internal.h"
yading@10: #include "formats.h"
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     int nb_out_samples;  ///< how many samples to output
yading@10:     AVAudioFifo *fifo;   ///< samples are queued here
yading@10:     int64_t next_out_pts;
yading@10:     int pad;
yading@10: } ASNSContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(ASNSContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
yading@10: 
yading@10: static const AVOption asetnsamples_options[] = {
yading@10:     { "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 },
yading@10:     { "n",              "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
yading@10:     { "pad", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
yading@10:     { "p",   "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(asetnsamples);
yading@10: 
yading@10: static av_cold int init(AVFilterContext *ctx)
yading@10: {
yading@10:     ASNSContext *asns = ctx->priv;
yading@10: 
yading@10:     asns->next_out_pts = AV_NOPTS_VALUE;
yading@10:     av_log(ctx, AV_LOG_VERBOSE, "nb_out_samples:%d pad:%d\n", asns->nb_out_samples, asns->pad);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold void uninit(AVFilterContext *ctx)
yading@10: {
yading@10:     ASNSContext *asns = ctx->priv;
yading@10:     av_audio_fifo_free(asns->fifo);
yading@10: }
yading@10: 
yading@10: static int config_props_output(AVFilterLink *outlink)
yading@10: {
yading@10:     ASNSContext *asns = outlink->src->priv;
yading@10:     int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout);
yading@10: 
yading@10:     asns->fifo = av_audio_fifo_alloc(outlink->format, nb_channels, asns->nb_out_samples);
yading@10:     if (!asns->fifo)
yading@10:         return AVERROR(ENOMEM);
yading@10:     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int push_samples(AVFilterLink *outlink)
yading@10: {
yading@10:     ASNSContext *asns = outlink->src->priv;
yading@10:     AVFrame *outsamples = NULL;
yading@10:     int ret, nb_out_samples, nb_pad_samples;
yading@10: 
yading@10:     if (asns->pad) {
yading@10:         nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0;
yading@10:         nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo));
yading@10:     } else {
yading@10:         nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));
yading@10:         nb_pad_samples = 0;
yading@10:     }
yading@10: 
yading@10:     if (!nb_out_samples)
yading@10:         return 0;
yading@10: 
yading@10:     outsamples = ff_get_audio_buffer(outlink, nb_out_samples);
yading@10:     if (!outsamples)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     av_audio_fifo_read(asns->fifo,
yading@10:                        (void **)outsamples->extended_data, nb_out_samples);
yading@10: 
yading@10:     if (nb_pad_samples)
yading@10:         av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,
yading@10:                                nb_pad_samples, av_get_channel_layout_nb_channels(outlink->channel_layout),
yading@10:                                outlink->format);
yading@10:     outsamples->nb_samples     = nb_out_samples;
yading@10:     outsamples->channel_layout = outlink->channel_layout;
yading@10:     outsamples->sample_rate    = outlink->sample_rate;
yading@10:     outsamples->pts = asns->next_out_pts;
yading@10: 
yading@10:     if (asns->next_out_pts != AV_NOPTS_VALUE)
yading@10:         asns->next_out_pts += nb_out_samples;
yading@10: 
yading@10:     ret = ff_filter_frame(outlink, outsamples);
yading@10:     if (ret < 0)
yading@10:         return ret;
yading@10:     return nb_out_samples;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     ASNSContext *asns = ctx->priv;
yading@10:     AVFilterLink *outlink = ctx->outputs[0];
yading@10:     int ret;
yading@10:     int nb_samples = insamples->nb_samples;
yading@10: 
yading@10:     if (av_audio_fifo_space(asns->fifo) < nb_samples) {
yading@10:         av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples);
yading@10:         ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples);
yading@10:         if (ret < 0) {
yading@10:             av_log(ctx, AV_LOG_ERROR,
yading@10:                    "Stretching audio fifo failed, discarded %d samples\n", nb_samples);
yading@10:             return -1;
yading@10:         }
yading@10:     }
yading@10:     av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
yading@10:     if (asns->next_out_pts == AV_NOPTS_VALUE)
yading@10:         asns->next_out_pts = insamples->pts;
yading@10:     av_frame_free(&insamples);
yading@10: 
yading@10:     while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
yading@10:         push_samples(outlink);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int request_frame(AVFilterLink *outlink)
yading@10: {
yading@10:     AVFilterLink *inlink = outlink->src->inputs[0];
yading@10:     int ret;
yading@10: 
yading@10:     ret = ff_request_frame(inlink);
yading@10:     if (ret == AVERROR_EOF) {
yading@10:         ret = push_samples(outlink);
yading@10:         return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF;
yading@10:     }
yading@10: 
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static const AVFilterPad asetnsamples_inputs[] = {
yading@10:     {
yading@10:         .name           = "default",
yading@10:         .type           = AVMEDIA_TYPE_AUDIO,
yading@10:         .filter_frame   = filter_frame,
yading@10:         .needs_writable = 1,
yading@10:     },
yading@10:     {  NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad asetnsamples_outputs[] = {
yading@10:     {
yading@10:         .name          = "default",
yading@10:         .type          = AVMEDIA_TYPE_AUDIO,
yading@10:         .request_frame = request_frame,
yading@10:         .config_props  = config_props_output,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_af_asetnsamples = {
yading@10:     .name           = "asetnsamples",
yading@10:     .description    = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."),
yading@10:     .priv_size      = sizeof(ASNSContext),
yading@10:     .init           = init,
yading@10:     .uninit         = uninit,
yading@10:     .inputs         = asetnsamples_inputs,
yading@10:     .outputs        = asetnsamples_outputs,
yading@10:     .priv_class     = &asetnsamples_class,
yading@10: };