LCOV - code coverage report
Current view: top level - libavfilter - af_extrastereo.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 31 38 81.6 %
Date: 2017-12-14 08:27:08 Functions: 2 2 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Copyright (c) 2015 The FFmpeg Project
       3             :  *
       4             :  * This file is part of FFmpeg.
       5             :  *
       6             :  * FFmpeg is free software; you can redistribute it and/or
       7             :  * modify it under the terms of the GNU Lesser General Public
       8             :  * License as published by the Free Software Foundation; either
       9             :  * version 2.1 of the License, or (at your option) any later version.
      10             :  *
      11             :  * FFmpeg is distributed in the hope that it will be useful,
      12             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      13             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14             :  * Lesser General Public License for more details.
      15             :  *
      16             :  * You should have received a copy of the GNU Lesser General Public
      17             :  * License along with FFmpeg; if not, write to the Free Software
      18             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      19             :  */
      20             : 
      21             : #include "libavutil/channel_layout.h"
      22             : #include "libavutil/opt.h"
      23             : #include "avfilter.h"
      24             : #include "audio.h"
      25             : #include "formats.h"
      26             : 
      27             : typedef struct ExtraStereoContext {
      28             :     const AVClass *class;
      29             :     float mult;
      30             :     int clip;
      31             : } ExtraStereoContext;
      32             : 
      33             : #define OFFSET(x) offsetof(ExtraStereoContext, x)
      34             : #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
      35             : 
      36             : static const AVOption extrastereo_options[] = {
      37             :     { "m", "set the difference coefficient", OFFSET(mult), AV_OPT_TYPE_FLOAT, {.dbl=2.5}, -10, 10, A },
      38             :     { "c", "enable clipping",                OFFSET(clip), AV_OPT_TYPE_BOOL,  {.i64=1},     0,  1, A },
      39             :     { NULL }
      40             : };
      41             : 
      42             : AVFILTER_DEFINE_CLASS(extrastereo);
      43             : 
      44           1 : static int query_formats(AVFilterContext *ctx)
      45             : {
      46           1 :     AVFilterFormats *formats = NULL;
      47           1 :     AVFilterChannelLayouts *layout = NULL;
      48             :     int ret;
      49             : 
      50           2 :     if ((ret = ff_add_format                 (&formats, AV_SAMPLE_FMT_FLT  )) < 0 ||
      51           2 :         (ret = ff_set_common_formats         (ctx     , formats            )) < 0 ||
      52           1 :         (ret = ff_add_channel_layout         (&layout , AV_CH_LAYOUT_STEREO)) < 0 ||
      53           1 :         (ret = ff_set_common_channel_layouts (ctx     , layout             )) < 0)
      54           0 :         return ret;
      55             : 
      56           1 :     formats = ff_all_samplerates();
      57           1 :     return ff_set_common_samplerates(ctx, formats);
      58             : }
      59             : 
      60          20 : static int filter_frame(AVFilterLink *inlink, AVFrame *in)
      61             : {
      62          20 :     AVFilterContext *ctx = inlink->dst;
      63          20 :     AVFilterLink *outlink = ctx->outputs[0];
      64          20 :     ExtraStereoContext *s = ctx->priv;
      65          20 :     const float *src = (const float *)in->data[0];
      66          20 :     const float mult = s->mult;
      67             :     AVFrame *out;
      68             :     float *dst;
      69             :     int n;
      70             : 
      71          20 :     if (av_frame_is_writable(in)) {
      72          20 :         out = in;
      73             :     } else {
      74           0 :         out = ff_get_audio_buffer(inlink, in->nb_samples);
      75           0 :         if (!out) {
      76           0 :             av_frame_free(&in);
      77           0 :             return AVERROR(ENOMEM);
      78             :         }
      79           0 :         av_frame_copy_props(out, in);
      80             :     }
      81          20 :     dst = (float *)out->data[0];
      82             : 
      83       20500 :     for (n = 0; n < in->nb_samples; n++) {
      84             :         float average, left, right;
      85             : 
      86       20480 :         left    = src[n * 2    ];
      87       20480 :         right   = src[n * 2 + 1];
      88       20480 :         average = (left + right) / 2.;
      89       20480 :         left    = average + mult * (left  - average);
      90       20480 :         right   = average + mult * (right - average);
      91             : 
      92       20480 :         if (s->clip) {
      93       20480 :             left  = av_clipf(left,  -1, 1);
      94       20480 :             right = av_clipf(right, -1, 1);
      95             :         }
      96             : 
      97       20480 :         dst[n * 2    ] = left;
      98       20480 :         dst[n * 2 + 1] = right;
      99             :     }
     100             : 
     101          20 :     if (out != in)
     102           0 :         av_frame_free(&in);
     103          20 :     return ff_filter_frame(outlink, out);
     104             : }
     105             : 
     106             : static const AVFilterPad inputs[] = {
     107             :     {
     108             :         .name         = "default",
     109             :         .type         = AVMEDIA_TYPE_AUDIO,
     110             :         .filter_frame = filter_frame,
     111             :     },
     112             :     { NULL }
     113             : };
     114             : 
     115             : static const AVFilterPad outputs[] = {
     116             :     {
     117             :         .name = "default",
     118             :         .type = AVMEDIA_TYPE_AUDIO,
     119             :     },
     120             :     { NULL }
     121             : };
     122             : 
     123             : AVFilter ff_af_extrastereo = {
     124             :     .name           = "extrastereo",
     125             :     .description    = NULL_IF_CONFIG_SMALL("Increase difference between stereo audio channels."),
     126             :     .query_formats  = query_formats,
     127             :     .priv_size      = sizeof(ExtraStereoContext),
     128             :     .priv_class     = &extrastereo_class,
     129             :     .inputs         = inputs,
     130             :     .outputs        = outputs,
     131             : };

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