| /* |
| * Copyright (c) 2011 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 |
| * audio volume filter |
| * based on ffmpeg.c code |
| */ |
| |
| #include "libavutil/audioconvert.h" |
| #include "libavutil/eval.h" |
| #include "avfilter.h" |
| |
| typedef struct { |
| double volume; |
| int volume_i; |
| } VolumeContext; |
| |
| static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) |
| { |
| VolumeContext *vol = ctx->priv; |
| char *tail; |
| int ret = 0; |
| |
| vol->volume = 1.0; |
| |
| if (args) { |
| /* parse the number as a decimal number */ |
| double d = strtod(args, &tail); |
| |
| if (*tail) { |
| if (!strcmp(tail, "dB")) { |
| /* consider the argument an adjustement in decibels */ |
| d = pow(10, d/20); |
| } else { |
| /* parse the argument as an expression */ |
| ret = av_expr_parse_and_eval(&d, args, NULL, NULL, |
| NULL, NULL, NULL, NULL, |
| NULL, 0, ctx); |
| } |
| } |
| |
| if (ret < 0) { |
| av_log(ctx, AV_LOG_ERROR, |
| "Invalid volume argument '%s'\n", args); |
| return AVERROR(EINVAL); |
| } |
| |
| if (d < 0 || d > 65536) { /* 65536 = INT_MIN / (128 * 256) */ |
| av_log(ctx, AV_LOG_ERROR, |
| "Negative or too big volume value %f\n", d); |
| return AVERROR(EINVAL); |
| } |
| |
| vol->volume = d; |
| } |
| |
| vol->volume_i = (int)(vol->volume * 256 + 0.5); |
| av_log(ctx, AV_LOG_INFO, "volume=%f\n", vol->volume); |
| return 0; |
| } |
| |
| static int query_formats(AVFilterContext *ctx) |
| { |
| AVFilterFormats *formats = NULL; |
| enum AVSampleFormat sample_fmts[] = { |
| AV_SAMPLE_FMT_U8, |
| AV_SAMPLE_FMT_S16, |
| AV_SAMPLE_FMT_S32, |
| AV_SAMPLE_FMT_FLT, |
| AV_SAMPLE_FMT_DBL, |
| AV_SAMPLE_FMT_NONE |
| }; |
| int packing_fmts[] = { AVFILTER_PACKED, -1 }; |
| |
| formats = avfilter_make_all_channel_layouts(); |
| if (!formats) |
| return AVERROR(ENOMEM); |
| avfilter_set_common_channel_layouts(ctx, formats); |
| |
| formats = avfilter_make_format_list(sample_fmts); |
| if (!formats) |
| return AVERROR(ENOMEM); |
| avfilter_set_common_sample_formats(ctx, formats); |
| |
| formats = avfilter_make_format_list(packing_fmts); |
| if (!formats) |
| return AVERROR(ENOMEM); |
| avfilter_set_common_packing_formats(ctx, formats); |
| |
| return 0; |
| } |
| |
| static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) |
| { |
| VolumeContext *vol = inlink->dst->priv; |
| AVFilterLink *outlink = inlink->dst->outputs[0]; |
| const int nb_samples = insamples->audio->nb_samples * |
| av_get_channel_layout_nb_channels(insamples->audio->channel_layout); |
| const double volume = vol->volume; |
| const int volume_i = vol->volume_i; |
| int i; |
| |
| if (volume_i != 256) { |
| switch (insamples->format) { |
| case AV_SAMPLE_FMT_U8: |
| { |
| uint8_t *p = (void *)insamples->data[0]; |
| for (i = 0; i < nb_samples; i++) { |
| int v = (((*p - 128) * volume_i + 128) >> 8) + 128; |
| *p++ = av_clip_uint8(v); |
| } |
| break; |
| } |
| case AV_SAMPLE_FMT_S16: |
| { |
| int16_t *p = (void *)insamples->data[0]; |
| for (i = 0; i < nb_samples; i++) { |
| int v = ((int64_t)*p * volume_i + 128) >> 8; |
| *p++ = av_clip_int16(v); |
| } |
| break; |
| } |
| case AV_SAMPLE_FMT_S32: |
| { |
| int32_t *p = (void *)insamples->data[0]; |
| for (i = 0; i < nb_samples; i++) { |
| int64_t v = (((int64_t)*p * volume_i + 128) >> 8); |
| *p++ = av_clipl_int32(v); |
| } |
| break; |
| } |
| case AV_SAMPLE_FMT_FLT: |
| { |
| float *p = (void *)insamples->data[0]; |
| float scale = (float)volume; |
| for (i = 0; i < nb_samples; i++) { |
| *p++ *= scale; |
| } |
| break; |
| } |
| case AV_SAMPLE_FMT_DBL: |
| { |
| double *p = (void *)insamples->data[0]; |
| for (i = 0; i < nb_samples; i++) { |
| *p *= volume; |
| p++; |
| } |
| break; |
| } |
| } |
| } |
| avfilter_filter_samples(outlink, insamples); |
| } |
| |
| AVFilter avfilter_af_volume = { |
| .name = "volume", |
| .description = NULL_IF_CONFIG_SMALL("Change input volume."), |
| .query_formats = query_formats, |
| .priv_size = sizeof(VolumeContext), |
| .init = init, |
| |
| .inputs = (const AVFilterPad[]) {{ .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .filter_samples = filter_samples, |
| .min_perms = AV_PERM_READ|AV_PERM_WRITE}, |
| { .name = NULL}}, |
| |
| .outputs = (const AVFilterPad[]) {{ .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, }, |
| { .name = NULL}}, |
| }; |