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FFmpeg/libavutil/channel_layout.c
James Almer 8c97449482 avutil/channel_layout: add a helper function to get the ambisonic order of a layout 
Signed-off-by: James Almer <jamrial@gmail.com>
2024-05-23 12:07:19 -03:00

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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 <stdlib.h>
#include <string.h>
#include "avassert.h"
#include "channel_layout.h"
#include "bprint.h"
#include "common.h"
#include "error.h"
#include "macros.h"
#include "mem.h"
#include "opt.h"
#define CHAN_IS_AMBI(x) ((x) >= AV_CHAN_AMBISONIC_BASE &&\
(x) <= AV_CHAN_AMBISONIC_END)
struct channel_name {
const char *name;
const char *description;
};
static const struct channel_name channel_names[] = {
[AV_CHAN_FRONT_LEFT ] = { "FL", "front left" },
[AV_CHAN_FRONT_RIGHT ] = { "FR", "front right" },
[AV_CHAN_FRONT_CENTER ] = { "FC", "front center" },
[AV_CHAN_LOW_FREQUENCY ] = { "LFE", "low frequency" },
[AV_CHAN_BACK_LEFT ] = { "BL", "back left" },
[AV_CHAN_BACK_RIGHT ] = { "BR", "back right" },
[AV_CHAN_FRONT_LEFT_OF_CENTER ] = { "FLC", "front left-of-center" },
[AV_CHAN_FRONT_RIGHT_OF_CENTER] = { "FRC", "front right-of-center" },
[AV_CHAN_BACK_CENTER ] = { "BC", "back center" },
[AV_CHAN_SIDE_LEFT ] = { "SL", "side left" },
[AV_CHAN_SIDE_RIGHT ] = { "SR", "side right" },
[AV_CHAN_TOP_CENTER ] = { "TC", "top center" },
[AV_CHAN_TOP_FRONT_LEFT ] = { "TFL", "top front left" },
[AV_CHAN_TOP_FRONT_CENTER ] = { "TFC", "top front center" },
[AV_CHAN_TOP_FRONT_RIGHT ] = { "TFR", "top front right" },
[AV_CHAN_TOP_BACK_LEFT ] = { "TBL", "top back left" },
[AV_CHAN_TOP_BACK_CENTER ] = { "TBC", "top back center" },
[AV_CHAN_TOP_BACK_RIGHT ] = { "TBR", "top back right" },
[AV_CHAN_STEREO_LEFT ] = { "DL", "downmix left" },
[AV_CHAN_STEREO_RIGHT ] = { "DR", "downmix right" },
[AV_CHAN_WIDE_LEFT ] = { "WL", "wide left" },
[AV_CHAN_WIDE_RIGHT ] = { "WR", "wide right" },
[AV_CHAN_SURROUND_DIRECT_LEFT ] = { "SDL", "surround direct left" },
[AV_CHAN_SURROUND_DIRECT_RIGHT] = { "SDR", "surround direct right" },
[AV_CHAN_LOW_FREQUENCY_2 ] = { "LFE2", "low frequency 2" },
[AV_CHAN_TOP_SIDE_LEFT ] = { "TSL", "top side left" },
[AV_CHAN_TOP_SIDE_RIGHT ] = { "TSR", "top side right" },
[AV_CHAN_BOTTOM_FRONT_CENTER ] = { "BFC", "bottom front center" },
[AV_CHAN_BOTTOM_FRONT_LEFT ] = { "BFL", "bottom front left" },
[AV_CHAN_BOTTOM_FRONT_RIGHT ] = { "BFR", "bottom front right" },
};
void av_channel_name_bprint(AVBPrint *bp, enum AVChannel channel_id)
{
if (channel_id >= AV_CHAN_AMBISONIC_BASE &&
channel_id <= AV_CHAN_AMBISONIC_END)
av_bprintf(bp, "AMBI%d", channel_id - AV_CHAN_AMBISONIC_BASE);
else if ((unsigned)channel_id < FF_ARRAY_ELEMS(channel_names) &&
channel_names[channel_id].name)
av_bprintf(bp, "%s", channel_names[channel_id].name);
else if (channel_id == AV_CHAN_NONE)
av_bprintf(bp, "NONE");
else if (channel_id == AV_CHAN_UNKNOWN)
av_bprintf(bp, "UNK");
else if (channel_id == AV_CHAN_UNUSED)
av_bprintf(bp, "UNSD");
else
av_bprintf(bp, "USR%d", channel_id);
}
int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel_id)
{
AVBPrint bp;
if (!buf && buf_size)
return AVERROR(EINVAL);
av_bprint_init_for_buffer(&bp, buf, buf_size);
av_channel_name_bprint(&bp, channel_id);
if (bp.len >= INT_MAX)
return AVERROR(ERANGE);
return bp.len + 1;
}
void av_channel_description_bprint(AVBPrint *bp, enum AVChannel channel_id)
{
if (channel_id >= AV_CHAN_AMBISONIC_BASE &&
channel_id <= AV_CHAN_AMBISONIC_END)
av_bprintf(bp, "ambisonic ACN %d", channel_id - AV_CHAN_AMBISONIC_BASE);
else if ((unsigned)channel_id < FF_ARRAY_ELEMS(channel_names) &&
channel_names[channel_id].description)
av_bprintf(bp, "%s", channel_names[channel_id].description);
else if (channel_id == AV_CHAN_NONE)
av_bprintf(bp, "none");
else if (channel_id == AV_CHAN_UNKNOWN)
av_bprintf(bp, "unknown");
else if (channel_id == AV_CHAN_UNUSED)
av_bprintf(bp, "unused");
else
av_bprintf(bp, "user %d", channel_id);
}
int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel_id)
{
AVBPrint bp;
if (!buf && buf_size)
return AVERROR(EINVAL);
av_bprint_init_for_buffer(&bp, buf, buf_size);
av_channel_description_bprint(&bp, channel_id);
if (bp.len >= INT_MAX)
return AVERROR(ERANGE);
return bp.len + 1;
}
enum AVChannel av_channel_from_string(const char *str)
{
int i;
char *endptr = (char *)str;
enum AVChannel id = AV_CHAN_NONE;
if (!strncmp(str, "AMBI", 4)) {
i = strtol(str + 4, NULL, 0);
if (i < 0 || i > AV_CHAN_AMBISONIC_END - AV_CHAN_AMBISONIC_BASE)
return AV_CHAN_NONE;
return AV_CHAN_AMBISONIC_BASE + i;
}
for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
if (channel_names[i].name && !strcmp(str, channel_names[i].name))
return i;
}
if (!strcmp(str, "UNK"))
return AV_CHAN_UNKNOWN;
if (!strcmp(str, "UNSD"))
return AV_CHAN_UNUSED;
if (!strncmp(str, "USR", 3)) {
const char *p = str + 3;
id = strtol(p, &endptr, 0);
}
if (id >= 0 && !*endptr)
return id;
return AV_CHAN_NONE;
}
struct channel_layout_name {
const char *name;
AVChannelLayout layout;
};
static const struct channel_layout_name channel_layout_map[] = {
{ "mono", AV_CHANNEL_LAYOUT_MONO },
{ "stereo", AV_CHANNEL_LAYOUT_STEREO },
{ "2.1", AV_CHANNEL_LAYOUT_2POINT1 },
{ "3.0", AV_CHANNEL_LAYOUT_SURROUND },
{ "3.0(back)", AV_CHANNEL_LAYOUT_2_1 },
{ "4.0", AV_CHANNEL_LAYOUT_4POINT0 },
{ "quad", AV_CHANNEL_LAYOUT_QUAD },
{ "quad(side)", AV_CHANNEL_LAYOUT_2_2 },
{ "3.1", AV_CHANNEL_LAYOUT_3POINT1 },
{ "5.0", AV_CHANNEL_LAYOUT_5POINT0_BACK },
{ "5.0(side)", AV_CHANNEL_LAYOUT_5POINT0 },
{ "4.1", AV_CHANNEL_LAYOUT_4POINT1 },
{ "5.1", AV_CHANNEL_LAYOUT_5POINT1_BACK },
{ "5.1(side)", AV_CHANNEL_LAYOUT_5POINT1 },
{ "6.0", AV_CHANNEL_LAYOUT_6POINT0 },
{ "6.0(front)", AV_CHANNEL_LAYOUT_6POINT0_FRONT },
{ "3.1.2", AV_CHANNEL_LAYOUT_3POINT1POINT2 },
{ "hexagonal", AV_CHANNEL_LAYOUT_HEXAGONAL },
{ "6.1", AV_CHANNEL_LAYOUT_6POINT1 },
{ "6.1(back)", AV_CHANNEL_LAYOUT_6POINT1_BACK },
{ "6.1(front)", AV_CHANNEL_LAYOUT_6POINT1_FRONT },
{ "7.0", AV_CHANNEL_LAYOUT_7POINT0 },
{ "7.0(front)", AV_CHANNEL_LAYOUT_7POINT0_FRONT },
{ "7.1", AV_CHANNEL_LAYOUT_7POINT1 },
{ "7.1(wide)", AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK },
{ "7.1(wide-side)", AV_CHANNEL_LAYOUT_7POINT1_WIDE },
{ "5.1.2", AV_CHANNEL_LAYOUT_5POINT1POINT2_BACK },
{ "octagonal", AV_CHANNEL_LAYOUT_OCTAGONAL },
{ "cube", AV_CHANNEL_LAYOUT_CUBE },
{ "5.1.4", AV_CHANNEL_LAYOUT_5POINT1POINT4_BACK },
{ "7.1.2", AV_CHANNEL_LAYOUT_7POINT1POINT2 },
{ "7.1.4", AV_CHANNEL_LAYOUT_7POINT1POINT4_BACK },
{ "7.2.3", AV_CHANNEL_LAYOUT_7POINT2POINT3 },
{ "9.1.4", AV_CHANNEL_LAYOUT_9POINT1POINT4_BACK },
{ "hexadecagonal", AV_CHANNEL_LAYOUT_HEXADECAGONAL },
{ "downmix", AV_CHANNEL_LAYOUT_STEREO_DOWNMIX, },
{ "22.2", AV_CHANNEL_LAYOUT_22POINT2, },
};
int av_channel_layout_custom_init(AVChannelLayout *channel_layout, int nb_channels)
{
AVChannelCustom *map;
if (nb_channels <= 0)
return AVERROR(EINVAL);
map = av_calloc(nb_channels, sizeof(*channel_layout->u.map));
if (!map)
return AVERROR(ENOMEM);
for (int i = 0; i < nb_channels; i++)
map[i].id = AV_CHAN_UNKNOWN;
channel_layout->order = AV_CHANNEL_ORDER_CUSTOM;
channel_layout->nb_channels = nb_channels;
channel_layout->u.map = map;
return 0;
}
int av_channel_layout_from_mask(AVChannelLayout *channel_layout,
uint64_t mask)
{
if (!mask)
return AVERROR(EINVAL);
channel_layout->order = AV_CHANNEL_ORDER_NATIVE;
channel_layout->nb_channels = av_popcount64(mask);
channel_layout->u.mask = mask;
return 0;
}
static int parse_channel_list(AVChannelLayout *ch_layout, const char *str)
{
int ret;
int nb_channels = 0;
AVChannelCustom *map = NULL;
AVChannelCustom custom = {0};
while (*str) {
char *channel, *chname;
int ret = av_opt_get_key_value(&str, "@", "+", AV_OPT_FLAG_IMPLICIT_KEY, &channel, &chname);
if (ret < 0) {
av_freep(&map);
return ret;
}
if (*str)
str++; // skip separator
if (!channel) {
channel = chname;
chname = NULL;
}
av_strlcpy(custom.name, chname ? chname : "", sizeof(custom.name));
custom.id = av_channel_from_string(channel);
av_free(channel);
av_free(chname);
if (custom.id == AV_CHAN_NONE) {
av_freep(&map);
return AVERROR(EINVAL);
}
av_dynarray2_add((void **)&map, &nb_channels, sizeof(custom), (void *)&custom);
if (!map)
return AVERROR(ENOMEM);
}
if (!nb_channels)
return AVERROR(EINVAL);
ch_layout->order = AV_CHANNEL_ORDER_CUSTOM;
ch_layout->u.map = map;
ch_layout->nb_channels = nb_channels;
ret = av_channel_layout_retype(ch_layout, 0, AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL);
av_assert0(ret == 0);
return 0;
}
int av_channel_layout_from_string(AVChannelLayout *channel_layout,
const char *str)
{
int i, matches, ret;
int channels = 0, nb_channels = 0;
char *chlist, *end;
uint64_t mask = 0;
/* channel layout names */
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
if (channel_layout_map[i].name && !strcmp(str, channel_layout_map[i].name)) {
*channel_layout = channel_layout_map[i].layout;
return 0;
}
}
/* This function is a channel layout initializer, so we have to
* zero-initialize before we start setting fields individually. */
memset(channel_layout, 0, sizeof(*channel_layout));
/* ambisonic */
if (!strncmp(str, "ambisonic ", 10)) {
const char *p = str + 10;
char *endptr;
AVChannelLayout extra = {0};
int order;
order = strtol(p, &endptr, 0);
if (order < 0 || order + 1 > INT_MAX / (order + 1) ||
(*endptr && *endptr != '+'))
return AVERROR(EINVAL);
channel_layout->order = AV_CHANNEL_ORDER_AMBISONIC;
channel_layout->nb_channels = (order + 1) * (order + 1);
if (*endptr) {
int ret = av_channel_layout_from_string(&extra, endptr + 1);
if (ret < 0)
return ret;
if (extra.nb_channels >= INT_MAX - channel_layout->nb_channels) {
av_channel_layout_uninit(&extra);
return AVERROR(EINVAL);
}
if (extra.order == AV_CHANNEL_ORDER_NATIVE) {
channel_layout->u.mask = extra.u.mask;
} else {
channel_layout->order = AV_CHANNEL_ORDER_CUSTOM;
channel_layout->u.map =
av_calloc(channel_layout->nb_channels + extra.nb_channels,
sizeof(*channel_layout->u.map));
if (!channel_layout->u.map) {
av_channel_layout_uninit(&extra);
return AVERROR(ENOMEM);
}
for (i = 0; i < channel_layout->nb_channels; i++)
channel_layout->u.map[i].id = AV_CHAN_AMBISONIC_BASE + i;
for (i = 0; i < extra.nb_channels; i++) {
enum AVChannel ch = av_channel_layout_channel_from_index(&extra, i);
if (CHAN_IS_AMBI(ch)) {
av_channel_layout_uninit(channel_layout);
av_channel_layout_uninit(&extra);
return AVERROR(EINVAL);
}
channel_layout->u.map[channel_layout->nb_channels + i].id = ch;
if (extra.order == AV_CHANNEL_ORDER_CUSTOM &&
extra.u.map[i].name[0])
av_strlcpy(channel_layout->u.map[channel_layout->nb_channels + i].name,
extra.u.map[i].name,
sizeof(channel_layout->u.map[channel_layout->nb_channels + i].name));
}
}
channel_layout->nb_channels += extra.nb_channels;
av_channel_layout_uninit(&extra);
}
return 0;
}
chlist = av_strdup(str);
if (!chlist)
return AVERROR(ENOMEM);
/* channel names */
matches = av_sscanf(str, "%d channels (%[^)]", &nb_channels, chlist);
ret = parse_channel_list(channel_layout, chlist);
av_freep(&chlist);
if (ret < 0 && ret != AVERROR(EINVAL))
return ret;
if (ret >= 0) {
end = strchr(str, ')');
if (matches == 2 && (nb_channels != channel_layout->nb_channels || !end || *++end)) {
av_channel_layout_uninit(channel_layout);
return AVERROR(EINVAL);
}
return 0;
}
errno = 0;
mask = strtoull(str, &end, 0);
/* channel layout mask */
if (!errno && !*end && !strchr(str, '-') && mask) {
av_channel_layout_from_mask(channel_layout, mask);
return 0;
}
errno = 0;
channels = strtol(str, &end, 10);
/* number of channels */
if (!errno && !strcmp(end, "c") && channels > 0) {
av_channel_layout_default(channel_layout, channels);
if (channel_layout->order == AV_CHANNEL_ORDER_NATIVE)
return 0;
}
/* number of unordered channels */
if (!errno && (!strcmp(end, "C") || !strcmp(end, " channels"))
&& channels > 0) {
channel_layout->order = AV_CHANNEL_ORDER_UNSPEC;
channel_layout->nb_channels = channels;
return 0;
}
return AVERROR(EINVAL);
}
void av_channel_layout_uninit(AVChannelLayout *channel_layout)
{
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM)
av_freep(&channel_layout->u.map);
memset(channel_layout, 0, sizeof(*channel_layout));
}
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
{
av_channel_layout_uninit(dst);
*dst = *src;
if (src->order == AV_CHANNEL_ORDER_CUSTOM) {
dst->u.map = av_malloc_array(src->nb_channels, sizeof(*dst->u.map));
if (!dst->u.map)
return AVERROR(ENOMEM);
memcpy(dst->u.map, src->u.map, src->nb_channels * sizeof(*src->u.map));
}
return 0;
}
static int64_t masked_description(const AVChannelLayout *channel_layout, int start_channel)
{
uint64_t mask = 0;
for (int i = start_channel; i < channel_layout->nb_channels; i++) {
enum AVChannel ch = channel_layout->u.map[i].id;
if (ch >= 0 && ch < 63 && mask < (1ULL << ch))
mask |= (1ULL << ch);
else
return AVERROR(EINVAL);
}
return mask;
}
static int has_channel_names(const AVChannelLayout *channel_layout)
{
if (channel_layout->order != AV_CHANNEL_ORDER_CUSTOM)
return 0;
for (int i = 0; i < channel_layout->nb_channels; i++)
if (channel_layout->u.map[i].name[0])
return 1;
return 0;
}
int av_channel_layout_ambisonic_order(const AVChannelLayout *channel_layout)
{
int i, highest_ambi, order;
if (channel_layout->order != AV_CHANNEL_ORDER_AMBISONIC &&
channel_layout->order != AV_CHANNEL_ORDER_CUSTOM)
return AVERROR(EINVAL);
highest_ambi = -1;
if (channel_layout->order == AV_CHANNEL_ORDER_AMBISONIC)
highest_ambi = channel_layout->nb_channels - av_popcount64(channel_layout->u.mask) - 1;
else {
const AVChannelCustom *map = channel_layout->u.map;
av_assert0(channel_layout->order == AV_CHANNEL_ORDER_CUSTOM);
for (i = 0; i < channel_layout->nb_channels; i++) {
int is_ambi = CHAN_IS_AMBI(map[i].id);
/* ambisonic following non-ambisonic */
if (i > 0 && is_ambi && !CHAN_IS_AMBI(map[i - 1].id))
return AVERROR(EINVAL);
/* non-default ordering */
if (is_ambi && map[i].id - AV_CHAN_AMBISONIC_BASE != i)
return AVERROR(EINVAL);
if (CHAN_IS_AMBI(map[i].id))
highest_ambi = i;
}
}
/* no ambisonic channels*/
if (highest_ambi < 0)
return AVERROR(EINVAL);
order = floor(sqrt(highest_ambi));
/* incomplete order - some harmonics are missing */
if ((order + 1) * (order + 1) != highest_ambi + 1)
return AVERROR(EINVAL);
return order;
}
static enum AVChannelOrder canonical_order(AVChannelLayout *channel_layout)
{
int has_known_channel = 0;
int order;
if (channel_layout->order != AV_CHANNEL_ORDER_CUSTOM)
return channel_layout->order;
if (has_channel_names(channel_layout))
return AV_CHANNEL_ORDER_CUSTOM;
for (int i = 0; i < channel_layout->nb_channels && !has_known_channel; i++)
if (channel_layout->u.map[i].id != AV_CHAN_UNKNOWN)
has_known_channel = 1;
if (!has_known_channel)
return AV_CHANNEL_ORDER_UNSPEC;
if (masked_description(channel_layout, 0) > 0)
return AV_CHANNEL_ORDER_NATIVE;
order = av_channel_layout_ambisonic_order(channel_layout);
if (order >= 0 && masked_description(channel_layout, (order + 1) * (order + 1)) >= 0)
return AV_CHANNEL_ORDER_AMBISONIC;
return AV_CHANNEL_ORDER_CUSTOM;
}
/**
* If the custom layout is n-th order standard-order ambisonic, with optional
* extra non-diegetic channels at the end, write its string description in bp.
* Return a negative error code otherwise.
*/
static int try_describe_ambisonic(AVBPrint *bp, const AVChannelLayout *channel_layout)
{
int nb_ambi_channels;
int order = av_channel_layout_ambisonic_order(channel_layout);
if (order < 0)
return order;
av_bprintf(bp, "ambisonic %d", order);
/* extra channels present */
nb_ambi_channels = (order + 1) * (order + 1);
if (nb_ambi_channels < channel_layout->nb_channels) {
AVChannelLayout extra = { 0 };
if (channel_layout->order == AV_CHANNEL_ORDER_AMBISONIC) {
extra.order = AV_CHANNEL_ORDER_NATIVE;
extra.nb_channels = av_popcount64(channel_layout->u.mask);
extra.u.mask = channel_layout->u.mask;
} else {
int64_t mask;
if (!has_channel_names(channel_layout) &&
(mask = masked_description(channel_layout, nb_ambi_channels)) > 0) {
extra.order = AV_CHANNEL_ORDER_NATIVE;
extra.nb_channels = av_popcount64(mask);
extra.u.mask = mask;
} else {
extra.order = AV_CHANNEL_ORDER_CUSTOM;
extra.nb_channels = channel_layout->nb_channels - nb_ambi_channels;
extra.u.map = channel_layout->u.map + nb_ambi_channels;
}
}
av_bprint_chars(bp, '+', 1);
av_channel_layout_describe_bprint(&extra, bp);
/* Not calling uninit here on extra because we don't own the u.map pointer */
}
return 0;
}
int av_channel_layout_describe_bprint(const AVChannelLayout *channel_layout,
AVBPrint *bp)
{
int i;
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_NATIVE:
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
if (channel_layout->u.mask == channel_layout_map[i].layout.u.mask) {
av_bprintf(bp, "%s", channel_layout_map[i].name);
return 0;
}
// fall-through
case AV_CHANNEL_ORDER_CUSTOM:
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM) {
int64_t mask;
int res = try_describe_ambisonic(bp, channel_layout);
if (res >= 0)
return 0;
if (!has_channel_names(channel_layout) &&
(mask = masked_description(channel_layout, 0)) > 0) {
AVChannelLayout native = { .order = AV_CHANNEL_ORDER_NATIVE,
.nb_channels = av_popcount64(mask),
.u.mask = mask };
return av_channel_layout_describe_bprint(&native, bp);
}
}
if (channel_layout->nb_channels)
av_bprintf(bp, "%d channels (", channel_layout->nb_channels);
for (i = 0; i < channel_layout->nb_channels; i++) {
enum AVChannel ch = av_channel_layout_channel_from_index(channel_layout, i);
if (i)
av_bprintf(bp, "+");
av_channel_name_bprint(bp, ch);
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM &&
channel_layout->u.map[i].name[0])
av_bprintf(bp, "@%s", channel_layout->u.map[i].name);
}
if (channel_layout->nb_channels) {
av_bprintf(bp, ")");
return 0;
}
// fall-through
case AV_CHANNEL_ORDER_UNSPEC:
av_bprintf(bp, "%d channels", channel_layout->nb_channels);
return 0;
case AV_CHANNEL_ORDER_AMBISONIC:
return try_describe_ambisonic(bp, channel_layout);
default:
return AVERROR(EINVAL);
}
}
int av_channel_layout_describe(const AVChannelLayout *channel_layout,
char *buf, size_t buf_size)
{
AVBPrint bp;
int ret;
if (!buf && buf_size)
return AVERROR(EINVAL);
av_bprint_init_for_buffer(&bp, buf, buf_size);
ret = av_channel_layout_describe_bprint(channel_layout, &bp);
if (ret < 0)
return ret;
if (bp.len >= INT_MAX)
return AVERROR(ERANGE);
return bp.len + 1;
}
enum AVChannel
av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout,
unsigned int idx)
{
int i;
if (idx >= channel_layout->nb_channels)
return AV_CHAN_NONE;
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_CUSTOM:
return channel_layout->u.map[idx].id;
case AV_CHANNEL_ORDER_AMBISONIC: {
int ambi_channels = channel_layout->nb_channels - av_popcount64(channel_layout->u.mask);
if (idx < ambi_channels)
return AV_CHAN_AMBISONIC_BASE + idx;
idx -= ambi_channels;
}
// fall-through
case AV_CHANNEL_ORDER_NATIVE:
for (i = 0; i < 64; i++) {
if ((1ULL << i) & channel_layout->u.mask && !idx--)
return i;
}
default:
return AV_CHAN_NONE;
}
}
enum AVChannel
av_channel_layout_channel_from_string(const AVChannelLayout *channel_layout,
const char *str)
{
int index = av_channel_layout_index_from_string(channel_layout, str);
if (index < 0)
return AV_CHAN_NONE;
return av_channel_layout_channel_from_index(channel_layout, index);
}
int av_channel_layout_index_from_channel(const AVChannelLayout *channel_layout,
enum AVChannel channel)
{
int i;
if (channel == AV_CHAN_NONE)
return AVERROR(EINVAL);
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_CUSTOM:
for (i = 0; i < channel_layout->nb_channels; i++)
if (channel_layout->u.map[i].id == channel)
return i;
return AVERROR(EINVAL);
case AV_CHANNEL_ORDER_AMBISONIC:
case AV_CHANNEL_ORDER_NATIVE: {
uint64_t mask = channel_layout->u.mask;
int ambi_channels = channel_layout->nb_channels - av_popcount64(mask);
if (channel_layout->order == AV_CHANNEL_ORDER_AMBISONIC &&
channel >= AV_CHAN_AMBISONIC_BASE) {
if (channel - AV_CHAN_AMBISONIC_BASE >= ambi_channels)
return AVERROR(EINVAL);
return channel - AV_CHAN_AMBISONIC_BASE;
}
if ((unsigned)channel > 63 || !(mask & (1ULL << channel)))
return AVERROR(EINVAL);
mask &= (1ULL << channel) - 1;
return av_popcount64(mask) + ambi_channels;
}
default:
return AVERROR(EINVAL);
}
}
int av_channel_layout_index_from_string(const AVChannelLayout *channel_layout,
const char *str)
{
char *chname;
enum AVChannel ch = AV_CHAN_NONE;
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_CUSTOM:
chname = strstr(str, "@");
if (chname) {
char buf[16];
chname++;
av_strlcpy(buf, str, FFMIN(sizeof(buf), chname - str));
if (!*chname)
chname = NULL;
ch = av_channel_from_string(buf);
if (ch == AV_CHAN_NONE && *buf)
return AVERROR(EINVAL);
}
for (int i = 0; chname && i < channel_layout->nb_channels; i++) {
if (!strcmp(chname, channel_layout->u.map[i].name) &&
(ch == AV_CHAN_NONE || ch == channel_layout->u.map[i].id))
return i;
}
// fall-through
case AV_CHANNEL_ORDER_AMBISONIC:
case AV_CHANNEL_ORDER_NATIVE:
ch = av_channel_from_string(str);
if (ch == AV_CHAN_NONE)
return AVERROR(EINVAL);
return av_channel_layout_index_from_channel(channel_layout, ch);
}
return AVERROR(EINVAL);
}
int av_channel_layout_check(const AVChannelLayout *channel_layout)
{
if (channel_layout->nb_channels <= 0)
return 0;
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_NATIVE:
return av_popcount64(channel_layout->u.mask) == channel_layout->nb_channels;
case AV_CHANNEL_ORDER_CUSTOM:
if (!channel_layout->u.map)
return 0;
for (int i = 0; i < channel_layout->nb_channels; i++) {
if (channel_layout->u.map[i].id == AV_CHAN_NONE)
return 0;
}
return 1;
case AV_CHANNEL_ORDER_AMBISONIC:
/* If non-diegetic channels are present, ensure they are taken into account */
return av_popcount64(channel_layout->u.mask) < channel_layout->nb_channels;
case AV_CHANNEL_ORDER_UNSPEC:
return 1;
default:
return 0;
}
}
int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1)
{
int i;
/* different channel counts -> not equal */
if (chl->nb_channels != chl1->nb_channels)
return 1;
/* if only one is unspecified -> not equal */
if ((chl->order == AV_CHANNEL_ORDER_UNSPEC) !=
(chl1->order == AV_CHANNEL_ORDER_UNSPEC))
return 1;
/* both are unspecified -> equal */
else if (chl->order == AV_CHANNEL_ORDER_UNSPEC)
return 0;
/* can compare masks directly */
if ((chl->order == AV_CHANNEL_ORDER_NATIVE ||
chl->order == AV_CHANNEL_ORDER_AMBISONIC) &&
chl->order == chl1->order)
return chl->u.mask != chl1->u.mask;
/* compare channel by channel */
for (i = 0; i < chl->nb_channels; i++)
if (av_channel_layout_channel_from_index(chl, i) !=
av_channel_layout_channel_from_index(chl1, i))
return 1;
return 0;
}
void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels)
{
int i;
for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
if (nb_channels == channel_layout_map[i].layout.nb_channels) {
*ch_layout = channel_layout_map[i].layout;
return;
}
ch_layout->order = AV_CHANNEL_ORDER_UNSPEC;
ch_layout->nb_channels = nb_channels;
}
const AVChannelLayout *av_channel_layout_standard(void **opaque)
{
uintptr_t i = (uintptr_t)*opaque;
const AVChannelLayout *ch_layout = NULL;
if (i < FF_ARRAY_ELEMS(channel_layout_map)) {
ch_layout = &channel_layout_map[i].layout;
*opaque = (void*)(i + 1);
}
return ch_layout;
}
uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
uint64_t mask)
{
uint64_t ret = 0;
int i;
switch (channel_layout->order) {
case AV_CHANNEL_ORDER_NATIVE:
case AV_CHANNEL_ORDER_AMBISONIC:
return channel_layout->u.mask & mask;
case AV_CHANNEL_ORDER_CUSTOM:
for (i = 0; i < 64; i++)
if (mask & (1ULL << i) && av_channel_layout_index_from_channel(channel_layout, i) >= 0)
ret |= (1ULL << i);
break;
}
return ret;
}
int av_channel_layout_retype(AVChannelLayout *channel_layout, enum AVChannelOrder order, int flags)
{
int allow_lossy = !(flags & AV_CHANNEL_LAYOUT_RETYPE_FLAG_LOSSLESS);
int lossy;
if (!av_channel_layout_check(channel_layout))
return AVERROR(EINVAL);
if (flags & AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL)
order = canonical_order(channel_layout);
if (channel_layout->order == order)
return 0;
switch (order) {
case AV_CHANNEL_ORDER_UNSPEC: {
int nb_channels = channel_layout->nb_channels;
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM) {
lossy = 0;
for (int i = 0; i < nb_channels; i++) {
if (channel_layout->u.map[i].id != AV_CHAN_UNKNOWN || channel_layout->u.map[i].name[0]) {
lossy = 1;
break;
}
}
} else {
lossy = 1;
}
if (!lossy || allow_lossy) {
void *opaque = channel_layout->opaque;
av_channel_layout_uninit(channel_layout);
channel_layout->order = AV_CHANNEL_ORDER_UNSPEC;
channel_layout->nb_channels = nb_channels;
channel_layout->opaque = opaque;
return lossy;
}
return AVERROR(ENOSYS);
}
case AV_CHANNEL_ORDER_NATIVE:
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM) {
int64_t mask = masked_description(channel_layout, 0);
if (mask < 0)
return AVERROR(ENOSYS);
lossy = has_channel_names(channel_layout);
if (!lossy || allow_lossy) {
void *opaque = channel_layout->opaque;
av_channel_layout_uninit(channel_layout);
av_channel_layout_from_mask(channel_layout, mask);
channel_layout->opaque = opaque;
return lossy;
}
}
return AVERROR(ENOSYS);
case AV_CHANNEL_ORDER_CUSTOM: {
AVChannelLayout custom = { 0 };
int ret = av_channel_layout_custom_init(&custom, channel_layout->nb_channels);
void *opaque = channel_layout->opaque;
if (ret < 0)
return ret;
if (channel_layout->order != AV_CHANNEL_ORDER_UNSPEC)
for (int i = 0; i < channel_layout->nb_channels; i++)
custom.u.map[i].id = av_channel_layout_channel_from_index(channel_layout, i);
av_channel_layout_uninit(channel_layout);
*channel_layout = custom;
channel_layout->opaque = opaque;
return 0;
}
case AV_CHANNEL_ORDER_AMBISONIC:
if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM) {
int64_t mask;
int nb_channels = channel_layout->nb_channels;
int order = av_channel_layout_ambisonic_order(channel_layout);
if (order < 0)
return AVERROR(ENOSYS);
mask = masked_description(channel_layout, (order + 1) * (order + 1));
if (mask < 0)
return AVERROR(ENOSYS);
lossy = has_channel_names(channel_layout);
if (!lossy || allow_lossy) {
void *opaque = channel_layout->opaque;
av_channel_layout_uninit(channel_layout);
channel_layout->order = AV_CHANNEL_ORDER_AMBISONIC;
channel_layout->nb_channels = nb_channels;
channel_layout->u.mask = mask;
channel_layout->opaque = opaque;
return lossy;
}
}
return AVERROR(ENOSYS);
default:
return AVERROR(EINVAL);
}
}
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