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avfilter/avf_showvolume: optionally display channel names 

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Paul B Mahol 2015-06-29 07:38:16 +00:00
parent e55e5be982
commit 9842d6707f
2 changed files with 33 additions and 0 deletions
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3
doc/filters.texi
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@ -12023,6 +12023,9 @@ The expression can use the following variables:
@item VOLUME
Current max volume of channel in dB.
@end table
@item t
If set, displays channel names. Default is enabled.
@end table
@section showwaves

30
libavfilter/avf_showvolume.c
View File

@ -23,6 +23,7 @@
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/xga_font_data.h"
#include "avfilter.h"
#include "formats.h"
#include "audio.h"
@ -38,6 +39,7 @@ typedef struct ShowVolumeContext {
AVFrame *out;
AVExpr *c_expr;
int draw_text;
} ShowVolumeContext;
#define OFFSET(x) offsetof(ShowVolumeContext, x)
@ -51,6 +53,7 @@ static const AVOption showvolume_options[] = {
{ "h", "set channel height", OFFSET(h), AV_OPT_TYPE_INT, {.i64=20}, 1, 100, FLAGS },
{ "f", "set fade", OFFSET(f), AV_OPT_TYPE_INT, {.i64=20}, 1, 255, FLAGS },
{ "c", "set volume color expression", OFFSET(color), AV_OPT_TYPE_STRING, {.str="if(gte(VOLUME,-2), if(gte(VOLUME,-1),0xff, 0xffff),0xff00)"}, 0, 0, FLAGS },
{ "t", "display channel names", OFFSET(draw_text), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
{ NULL }
};
@ -133,6 +136,29 @@ static int config_output(AVFilterLink *outlink)
return 0;
}
static void drawtext(AVFrame *pic, int x, int y, const char *txt)
{
const uint8_t *font;
int font_height;
int i;
font = avpriv_cga_font, font_height = 8;
for (i = 0; txt[i]; i++) {
int char_y, mask;
uint8_t *p = pic->data[0] + y*pic->linesize[0] + (x + i*8)*4;
for (char_y = 0; char_y < font_height; char_y++) {
for (mask = 0x80; mask; mask >>= 1) {
if (font[txt[i] * font_height + char_y] & mask)
AV_WN32(p, ~AV_RN32(p));
p += 4;
}
p += pic->linesize[0] - 8*4;
}
}
}
static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
{
AVFilterContext *ctx = inlink->dst;
@ -183,6 +209,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
for (k = 0; k < s->w * max; k++)
AV_WN32A(dst + k * 4, color);
}
if (s->h >= 8 && s->draw_text)
drawtext(s->out, 2, c * (s->h + s->b) + (s->h - 8) / 2,
av_get_channel_name(av_channel_layout_extract_channel(insamples->channel_layout, c)));
}
av_frame_free(&insamples);