Stefano Sabatini
14 years ago
parent
1fc7077115
commit
618ac71354
6 changed files with 247 additions and 2 deletions
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/*
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* Copyright (c) 2011 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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* audio volume filter |
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* based on ffmpeg.c code |
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*/ |
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#include "libavutil/audioconvert.h" |
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#include "libavutil/eval.h" |
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#include "avfilter.h" |
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typedef struct { |
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double volume; |
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int volume_i; |
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} VolumeContext; |
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) |
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{ |
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VolumeContext *vol = ctx->priv; |
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char *tail; |
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int ret = 0; |
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vol->volume = 1.0; |
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if (args) { |
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/* parse the number as a decimal number */ |
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double d = strtod(args, &tail); |
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if (*tail) { |
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if (!strcmp(tail, "dB")) { |
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/* consider the argument an adjustement in decibels */ |
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if (!strcmp(tail, "dB")) { |
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d = exp10(d/20); |
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} |
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} else { |
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/* parse the argument as an expression */ |
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ret = av_expr_parse_and_eval(&d, args, NULL, NULL, |
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NULL, NULL, NULL, NULL, |
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NULL, 0, ctx); |
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} |
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} |
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if (ret < 0) { |
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av_log(ctx, AV_LOG_ERROR, |
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"Invalid volume argument '%s'\n", args); |
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return AVERROR(EINVAL); |
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} |
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if (d < 0 || d > 65536) { /* 65536 = INT_MIN / (128 * 256) */ |
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av_log(ctx, AV_LOG_ERROR, |
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"Negative or too big volume value %f\n", d); |
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return AVERROR(EINVAL); |
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} |
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vol->volume = d; |
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} |
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vol->volume_i = (int)(vol->volume * 256 + 0.5); |
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av_log(ctx, AV_LOG_INFO, "volume=%f\n", vol->volume); |
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return 0; |
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} |
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static int query_formats(AVFilterContext *ctx) |
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{ |
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AVFilterFormats *formats = NULL; |
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enum AVSampleFormat sample_fmts[] = { |
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AV_SAMPLE_FMT_U8, |
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AV_SAMPLE_FMT_S16, |
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AV_SAMPLE_FMT_S32, |
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AV_SAMPLE_FMT_FLT, |
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AV_SAMPLE_FMT_DBL, |
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AV_SAMPLE_FMT_NONE |
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}; |
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int packing_fmts[] = { AVFILTER_PACKED, -1 }; |
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formats = avfilter_make_all_channel_layouts(); |
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if (!formats) |
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return AVERROR(ENOMEM); |
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avfilter_set_common_channel_layouts(ctx, formats); |
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formats = avfilter_make_format_list(sample_fmts); |
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if (!formats) |
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return AVERROR(ENOMEM); |
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avfilter_set_common_sample_formats(ctx, formats); |
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formats = avfilter_make_format_list(packing_fmts); |
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if (!formats) |
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return AVERROR(ENOMEM); |
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avfilter_set_common_packing_formats(ctx, formats); |
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return 0; |
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} |
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static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) |
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{ |
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VolumeContext *vol = inlink->dst->priv; |
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AVFilterLink *outlink = inlink->dst->outputs[0]; |
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const int nb_samples = insamples->audio->nb_samples * |
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av_get_channel_layout_nb_channels(insamples->audio->channel_layout); |
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const double volume = vol->volume; |
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const int volume_i = vol->volume_i; |
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int i; |
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if (volume_i != 256) { |
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switch (insamples->format) { |
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case AV_SAMPLE_FMT_U8: |
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{ |
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uint8_t *p = (void *)insamples->data[0]; |
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for (i = 0; i < nb_samples; i++) { |
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int v = (((*p - 128) * volume_i + 128) >> 8) + 128; |
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*p++ = av_clip_uint8(v); |
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} |
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break; |
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} |
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case AV_SAMPLE_FMT_S16: |
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{ |
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int16_t *p = (void *)insamples->data[0]; |
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for (i = 0; i < nb_samples; i++) { |
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int v = ((int64_t)*p * volume_i + 128) >> 8; |
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*p++ = av_clip_int16(v); |
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} |
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break; |
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} |
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case AV_SAMPLE_FMT_S32: |
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{ |
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int32_t *p = (void *)insamples->data[0]; |
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for (i = 0; i < nb_samples; i++) { |
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int64_t v = (((int64_t)*p * volume_i + 128) >> 8); |
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*p++ = av_clipl_int32(v); |
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} |
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break; |
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} |
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case AV_SAMPLE_FMT_FLT: |
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{ |
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float *p = (void *)insamples->data[0]; |
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float scale = (float)volume; |
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for (i = 0; i < nb_samples; i++) { |
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*p++ *= scale; |
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} |
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break; |
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} |
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case AV_SAMPLE_FMT_DBL: |
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{ |
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double *p = (void *)insamples->data[0]; |
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for (i = 0; i < nb_samples; i++) { |
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*p *= volume; |
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p++; |
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} |
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break; |
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} |
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} |
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} |
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avfilter_filter_samples(outlink, insamples); |
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} |
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AVFilter avfilter_af_volume = { |
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.name = "volume", |
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.description = NULL_IF_CONFIG_SMALL("Change input volume."), |
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.query_formats = query_formats, |
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.priv_size = sizeof(VolumeContext), |
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.init = init, |
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.inputs = (AVFilterPad[]) {{ .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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{ .name = NULL}}, |
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.outputs = (AVFilterPad[]) {{ .name = "default", |
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.type = AVMEDIA_TYPE_AUDIO, }, |
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{ .name = NULL}}, |
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}; |
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