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FFmpeg/libavutil/channel_layout.c
Martin Cracauer 73d1398f0c avutil/channel_layout: AV_CH_LAYOUT_6POINT1_BACK not reachable in parsing 
Trying to make heads and tails out of DTS 6.1 I can across this typo.

I also noticed that this wiki page is incorrect or misleading, the
channel order for 6.1 given does not match the source code.  At the
least it should be clarified that the layout given does not apply to
DTS.  https://trac.ffmpeg.org/wiki/AudioChannelManipulation

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2016-03-10 21:24:25 +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;
}
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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