mirror of https://github.com/FFmpeg/FFmpeg.git
This filter changes the number of samples on single output operation. Based on a patch by Andrey Utkin <andrey.krieger.utkin@gmail.com>.pull/59/head
Stefano Sabatini
13 years ago
parent
e20530add7
commit
2b1fc5621d
6 changed files with 240 additions and 1 deletions
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/*
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* Copyright (c) 2012 Andrey Utkin |
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* Copyright (c) 2012 Stefano Sabatini |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file |
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* Filter that changes number of samples on single output operation |
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*/ |
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#include "libavutil/audio_fifo.h" |
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#include "libavutil/avassert.h" |
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#include "libavutil/opt.h" |
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#include "avfilter.h" |
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#include "audio.h" |
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#include "formats.h" |
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typedef struct { |
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const AVClass *class; |
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int nb_out_samples; ///< how many samples to output
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AVAudioFifo *fifo; ///< samples are queued here
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int64_t next_out_pts; |
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int req_fullfilled; |
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int pad; |
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} ASNSContext; |
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#define OFFSET(x) offsetof(ASNSContext, x) |
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static const AVOption asns_options[] = { |
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{ "pad", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.dbl=1}, 0, 1 }, |
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{ "p", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.dbl=1}, 0, 1 }, |
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{ "nb_out_samples", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.dbl=1024}, 1, INT_MAX }, |
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{ "n", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.dbl=1024}, 1, INT_MAX }, |
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{ NULL } |
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}; |
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static const AVClass asns_class = { |
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"asetnsamples", |
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av_default_item_name, |
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asns_options |
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}; |
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) |
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{ |
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ASNSContext *asns = ctx->priv; |
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int err; |
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asns->class = &asns_class; |
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av_opt_set_defaults(asns); |
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if ((err = av_set_options_string(asns, args, "=", ":")) < 0) { |
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av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args); |
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return err; |
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} |
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asns->next_out_pts = AV_NOPTS_VALUE; |
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av_log(ctx, AV_LOG_INFO, "nb_out_samples:%d pad:%d\n", asns->nb_out_samples, asns->pad); |
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return 0; |
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} |
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static av_cold void uninit(AVFilterContext *ctx) |
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{ |
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ASNSContext *asns = ctx->priv; |
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av_audio_fifo_free(asns->fifo); |
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} |
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static int config_props_output(AVFilterLink *outlink) |
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{ |
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ASNSContext *asns = outlink->src->priv; |
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int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout); |
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asns->fifo = av_audio_fifo_alloc(outlink->format, nb_channels, asns->nb_out_samples); |
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if (!asns->fifo) |
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return AVERROR(ENOMEM); |
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return 0; |
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} |
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static int push_samples(AVFilterLink *outlink) |
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{ |
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ASNSContext *asns = outlink->src->priv; |
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AVFilterBufferRef *outsamples = NULL; |
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int nb_out_samples, nb_pad_samples; |
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if (asns->pad) { |
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nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0; |
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nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo)); |
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} else { |
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nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo)); |
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nb_pad_samples = 0; |
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} |
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if (!nb_out_samples) |
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return 0; |
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outsamples = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_out_samples); |
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av_assert0(outsamples); |
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av_audio_fifo_read(asns->fifo, |
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(void **)outsamples->extended_data, nb_out_samples); |
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if (nb_pad_samples) |
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av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples, |
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nb_pad_samples, av_get_channel_layout_nb_channels(outlink->channel_layout), |
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outlink->format); |
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outsamples->audio->nb_samples = nb_out_samples; |
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outsamples->audio->channel_layout = outlink->channel_layout; |
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outsamples->audio->sample_rate = outlink->sample_rate; |
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outsamples->pts = asns->next_out_pts; |
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if (asns->next_out_pts != AV_NOPTS_VALUE) |
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asns->next_out_pts += nb_out_samples; |
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ff_filter_samples(outlink, outsamples); |
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asns->req_fullfilled = 1; |
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return nb_out_samples; |
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} |
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static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) |
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{ |
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AVFilterContext *ctx = inlink->dst; |
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ASNSContext *asns = ctx->priv; |
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AVFilterLink *outlink = ctx->outputs[0]; |
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int ret; |
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int nb_samples = insamples->audio->nb_samples; |
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if (av_audio_fifo_space(asns->fifo) < nb_samples) { |
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av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples); |
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ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples); |
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if (ret < 0) { |
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av_log(ctx, AV_LOG_ERROR, |
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"Stretching audio fifo failed, discarded %d samples\n", nb_samples); |
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return; |
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} |
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} |
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av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples); |
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if (asns->next_out_pts == AV_NOPTS_VALUE) |
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asns->next_out_pts = insamples->pts; |
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avfilter_unref_buffer(insamples); |
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if (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples) |
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push_samples(outlink); |
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} |
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static int request_frame(AVFilterLink *outlink) |
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{ |
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ASNSContext *asns = outlink->src->priv; |
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AVFilterLink *inlink = outlink->src->inputs[0]; |
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int ret; |
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asns->req_fullfilled = 0; |
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do { |
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ret = avfilter_request_frame(inlink); |
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} while (!asns->req_fullfilled && ret >= 0); |
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if (ret == AVERROR_EOF) |
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while (push_samples(outlink)) |
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; |
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return ret; |
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} |
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AVFilter avfilter_af_asetnsamples = { |
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.name = "asetnsamples", |
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.description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."), |
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.priv_size = sizeof(ASNSContext), |
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.init = init, |
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.uninit = uninit, |
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.inputs = (const AVFilterPad[]) { |
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{ |
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.name = "default", |
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.type = AVMEDIA_TYPE_AUDIO, |
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.filter_samples = filter_samples, |
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.min_perms = AV_PERM_READ|AV_PERM_WRITE |
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}, |
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{ .name = NULL } |
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}, |
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.outputs = (const AVFilterPad[]) { |
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{ |
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.name = "default", |
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.type = AVMEDIA_TYPE_AUDIO, |
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.request_frame = request_frame, |
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.config_props = config_props_output, |
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}, |
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{ .name = NULL } |
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}, |
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}; |
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