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FFmpeg/libavutil/channel_layout.c
Marton Balint c4618f842a avutil/channel_layout: add av_get_extended_channel_layout 
Return a channel layout and the number of channels based on the specified name.

This function is similar to av_get_channel_layout(), but can also parse unknown
channel layout specifications.

Unknown channel layout specifications are a decimal number and a capital 'C'
suffix, in order to not break compatibility with the lowercase 'c' suffix,
which is used for a guessed channel layout with the specified number of
channels.

Signed-off-by: Marton Balint <cus@passwd.hu>
2017-01-24 23:51:36 +01:00

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/*
* Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* 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 channel layout utility functions
*/
#include <stdint.h>
#include "avstring.h"
#include "avutil.h"
#include "channel_layout.h"
#include "bprint.h"
#include "common.h"
struct channel_name {
const char *name;
const char *description;
};
static const struct channel_name channel_names[] = {
[0] = { "FL", "front left" },
[1] = { "FR", "front right" },
[2] = { "FC", "front center" },
[3] = { "LFE", "low frequency" },
[4] = { "BL", "back left" },
[5] = { "BR", "back right" },
[6] = { "FLC", "front left-of-center" },
[7] = { "FRC", "front right-of-center" },
[8] = { "BC", "back center" },
[9] = { "SL", "side left" },
[10] = { "SR", "side right" },
[11] = { "TC", "top center" },
[12] = { "TFL", "top front left" },
[13] = { "TFC", "top front center" },
[14] = { "TFR", "top front right" },
[15] = { "TBL", "top back left" },
[16] = { "TBC", "top back center" },
[17] = { "TBR", "top back right" },
[29] = { "DL", "downmix left" },
[30] = { "DR", "downmix right" },
[31] = { "WL", "wide left" },
[32] = { "WR", "wide right" },
[33] = { "SDL", "surround direct left" },
[34] = { "SDR", "surround direct right" },
[35] = { "LFE2", "low frequency 2" },
};
static const char *get_channel_name(int channel_id)
{
if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
return NULL;
return channel_names[channel_id].name;
}
static const struct {
const char *name;
int nb_channels;
uint64_t layout;
} channel_layout_map[] = {
{ "mono", 1, AV_CH_LAYOUT_MONO },
{ "stereo", 2, AV_CH_LAYOUT_STEREO },
{ "2.1", 3, AV_CH_LAYOUT_2POINT1 },
{ "3.0", 3, AV_CH_LAYOUT_SURROUND },
{ "3.0(back)", 3, AV_CH_LAYOUT_2_1 },
{ "4.0", 4, AV_CH_LAYOUT_4POINT0 },
{ "quad", 4, AV_CH_LAYOUT_QUAD },
{ "quad(side)", 4, AV_CH_LAYOUT_2_2 },
{ "3.1", 4, AV_CH_LAYOUT_3POINT1 },
{ "5.0", 5, AV_CH_LAYOUT_5POINT0_BACK },
{ "5.0(side)", 5, AV_CH_LAYOUT_5POINT0 },
{ "4.1", 5, AV_CH_LAYOUT_4POINT1 },
{ "5.1", 6, AV_CH_LAYOUT_5POINT1_BACK },
{ "5.1(side)", 6, AV_CH_LAYOUT_5POINT1 },
{ "6.0", 6, AV_CH_LAYOUT_6POINT0 },
{ "6.0(front)", 6, AV_CH_LAYOUT_6POINT0_FRONT },
{ "hexagonal", 6, AV_CH_LAYOUT_HEXAGONAL },
{ "6.1", 7, AV_CH_LAYOUT_6POINT1 },
{ "6.1(back)", 7, AV_CH_LAYOUT_6POINT1_BACK },
{ "6.1(front)", 7, AV_CH_LAYOUT_6POINT1_FRONT },
{ "7.0", 7, AV_CH_LAYOUT_7POINT0 },
{ "7.0(front)", 7, AV_CH_LAYOUT_7POINT0_FRONT },
{ "7.1", 8, AV_CH_LAYOUT_7POINT1 },
{ "7.1(wide)", 8, AV_CH_LAYOUT_7POINT1_WIDE_BACK },
{ "7.1(wide-side)", 8, AV_CH_LAYOUT_7POINT1_WIDE },
{ "octagonal", 8, AV_CH_LAYOUT_OCTAGONAL },
{ "hexadecagonal", 16, AV_CH_LAYOUT_HEXADECAGONAL },
{ "downmix", 2, AV_CH_LAYOUT_STEREO_DOWNMIX, },
};
static uint64_t get_channel_layout_single(const char *name, int name_len)
{
int i;
char *end;
int64_t layout;
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
if (strlen(channel_layout_map[i].name) == name_len &&
!memcmp(channel_layout_map[i].name, name, name_len))
return channel_layout_map[i].layout;
}
for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
if (channel_names[i].name &&
strlen(channel_names[i].name) == name_len &&
!memcmp(channel_names[i].name, name, name_len))
return (int64_t)1 << i;
errno = 0;
i = strtol(name, &end, 10);
if (!errno && (end + 1 - name == name_len && *end == 'c'))
return av_get_default_channel_layout(i);
errno = 0;
layout = strtoll(name, &end, 0);
if (!errno && end - name == name_len)
return FFMAX(layout, 0);
return 0;
}
uint64_t av_get_channel_layout(const char *name)
{
const char *n, *e;
const char *name_end = name + strlen(name);
int64_t layout = 0, layout_single;
for (n = name; n < name_end; n = e + 1) {
for (e = n; e < name_end && *e != '+' && *e != '|'; e++);
layout_single = get_channel_layout_single(n, e - n);
if (!layout_single)
return 0;
layout |= layout_single;
}
return layout;
}
int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels)
{
int nb = 0;
char *end;
uint64_t layout = av_get_channel_layout(name);
if (layout) {
*channel_layout = layout;
*nb_channels = av_get_channel_layout_nb_channels(layout);
return 0;
}
nb = strtol(name, &end, 10);
if (!errno && *end == 'C' && *(end + 1) == '\0' && nb > 0 && nb < 64) {
*channel_layout = 0;
*nb_channels = nb;
return 0;
}
return AVERROR(EINVAL);
}
void av_bprint_channel_layout(struct AVBPrint *bp,
int nb_channels, uint64_t channel_layout)
{
int i;
if (nb_channels <= 0)
nb_channels = av_get_channel_layout_nb_channels(channel_layout);
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
if (nb_channels == channel_layout_map[i].nb_channels &&
channel_layout == channel_layout_map[i].layout) {
av_bprintf(bp, "%s", channel_layout_map[i].name);
return;
}
av_bprintf(bp, "%d channels", nb_channels);
if (channel_layout) {
int i, ch;
av_bprintf(bp, " (");
for (i = 0, ch = 0; i < 64; i++) {
if ((channel_layout & (UINT64_C(1) << i))) {
const char *name = get_channel_name(i);
if (name) {
if (ch > 0)
av_bprintf(bp, "+");
av_bprintf(bp, "%s", name);
}
ch++;
}
}
av_bprintf(bp, ")");
}
}
void av_get_channel_layout_string(char *buf, int buf_size,
int nb_channels, uint64_t channel_layout)
{
AVBPrint bp;
av_bprint_init_for_buffer(&bp, buf, buf_size);
av_bprint_channel_layout(&bp, nb_channels, channel_layout);
}
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
{
return av_popcount64(channel_layout);
}
int64_t av_get_default_channel_layout(int nb_channels) {
int i;
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
if (nb_channels == channel_layout_map[i].nb_channels)
return channel_layout_map[i].layout;
return 0;
}
int av_get_channel_layout_channel_index(uint64_t channel_layout,
uint64_t channel)
{
if (!(channel_layout & channel) ||
av_get_channel_layout_nb_channels(channel) != 1)
return AVERROR(EINVAL);
channel_layout &= channel - 1;
return av_get_channel_layout_nb_channels(channel_layout);
}
const char *av_get_channel_name(uint64_t channel)
{
int i;
if (av_get_channel_layout_nb_channels(channel) != 1)
return NULL;
for (i = 0; i < 64; i++)
if ((1ULL<<i) & channel)
return get_channel_name(i);
return NULL;
}
const char *av_get_channel_description(uint64_t channel)
{
int i;
if (av_get_channel_layout_nb_channels(channel) != 1)
return NULL;
for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
if ((1ULL<<i) & channel)
return channel_names[i].description;
return NULL;
}
uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
{
int i;
if (av_get_channel_layout_nb_channels(channel_layout) <= index)
return 0;
for (i = 0; i < 64; i++) {
if ((1ULL << i) & channel_layout && !index--)
return 1ULL << i;
}
return 0;
}
int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
const char **name)
{
if (index >= FF_ARRAY_ELEMS(channel_layout_map))
return AVERROR_EOF;
if (layout) *layout = channel_layout_map[index].layout;
if (name) *name = channel_layout_map[index].name;
return 0;
}
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