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mirror of https://github.com/mpv-player/mpv synced 2024-11-18 21:16:10 +01:00
mpv/audio/chmap.c
wm4 ab8f28a672 audio: add channel map selection function
The point is selecting a minimal fallback. The AOs will call this
through the AO API, so it will be possible to add options affecting
the general channel layout selection.

It provides the following mechanism to AOs:
- forcing the correct channel order
- downmixing to stereo if no layout is available
- allow 5.1 <-> 5.1(side) fallback
- handling "unknown" channel layouts

This is quite weak and lots of code/complexity for little gain. All AOs
already made sure the channel order was correct, and the fallback is of
little value, and could perhaps be done in the frontend instead, like
stereo downmixing with --channels=2 is handled. But I'm not really sure
how this stuff should _really_ work, and the new code will hopefully
provides enough flexibility to make radical changes to channel layout
negotiation easier.
2013-05-12 21:24:57 +02:00

487 lines
17 KiB
C

/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <assert.h>
#include "core/mp_msg.h"
#include "chmap.h"
// Names taken from libavutil/channel_layout.c (Not accessible by API.)
// Use of these names is hard-coded in some places (e.g. ao_alsa.c)
static const char *speaker_names[MP_SPEAKER_ID_COUNT][2] = {
[MP_SPEAKER_ID_FL] = {"fl", "front left"},
[MP_SPEAKER_ID_FR] = {"fr", "front right"},
[MP_SPEAKER_ID_FC] = {"fc", "front center"},
[MP_SPEAKER_ID_LFE] = {"lfe", "low frequency"},
[MP_SPEAKER_ID_BL] = {"bl", "back left"},
[MP_SPEAKER_ID_BR] = {"br", "back right"},
[MP_SPEAKER_ID_FLC] = {"flc", "front left-of-center"},
[MP_SPEAKER_ID_FRC] = {"frc", "front right-of-center"},
[MP_SPEAKER_ID_BC] = {"bc", "back center"},
[MP_SPEAKER_ID_SL] = {"sl", "side left"},
[MP_SPEAKER_ID_SR] = {"sr", "side right"},
[MP_SPEAKER_ID_TC] = {"tc", "top center"},
[MP_SPEAKER_ID_TFL] = {"tfl", "top front left"},
[MP_SPEAKER_ID_TFC] = {"tfc", "top front center"},
[MP_SPEAKER_ID_TFR] = {"tfr", "top front right"},
[MP_SPEAKER_ID_TBL] = {"tbl", "top back left"},
[MP_SPEAKER_ID_TBC] = {"tbc", "top back center"},
[MP_SPEAKER_ID_TBR] = {"tbr", "top back right"},
[MP_SPEAKER_ID_DL] = {"dl", "downmix left"},
[MP_SPEAKER_ID_DR] = {"dr", "downmix right"},
[MP_SPEAKER_ID_WL] = {"wl", "wide left"},
[MP_SPEAKER_ID_WR] = {"wr", "wide right"},
[MP_SPEAKER_ID_SDL] = {"sdl", "surround direct left"},
[MP_SPEAKER_ID_SDR] = {"sdr", "surround direct right"},
[MP_SPEAKER_ID_LFE2] = {"lfe2", "low frequency 2"},
};
// Names taken from libavutil/channel_layout.c (Not accessible by API.)
// Channel order corresponds to lavc/waveex, except for the alsa entries.
static const char *std_layout_names[][2] = {
{"empty", ""}, // not in lavc
{"mono", "fc"},
{"stereo", "fl-fr"},
{"2.1", "fl-fr-lfe"},
{"3.0", "fl-fr-fc"},
{"3.0(back)", "fl-fr-bc"},
{"4.0", "fl-fr-fc-bc"},
{"quad", "fl-fr-bl-br"},
{"quad(side)", "fl-fr-sl-sr"},
{"3.1", "fl-fr-fc-lfe"},
{"5.0", "fl-fr-fc-bl-br"},
{"5.0(alsa)", "fl-fr-bl-br-fc"}, // not in lavc
{"5.0(side)", "fl-fr-fc-sl-sr"},
{"4.1", "fl-fr-fc-lfe-bc"},
{"4.1(alsa)", "fl-fr-bl-br-lfe"}, // not in lavc
{"5.1", "fl-fr-fc-lfe-bl-br"},
{"5.1(alsa)", "fl-fr-bl-br-fc-lfe"}, // not in lavc
{"5.1(side)", "fl-fr-fc-lfe-sl-sr"},
{"6.0", "fl-fr-fc-bc-sl-sr"},
{"6.0(front)", "fl-fr-flc-frc-sl-sr"},
{"hexagonal", "fl-fr-fc-bl-br-bc"},
{"6.1", "fl-fr-fc-lfe-bl-br-bc"},
{"6.1(front)", "fl-fr-lfe-flc-frc-sl-sr"},
{"7.0", "fl-fr-fc-bl-br-sl-sr"},
{"7.0(front)", "fl-fr-fc-flc-frc-sl-sr"},
{"7.1", "fl-fr-fc-lfe-bl-br-sl-sr"},
{"7.1(alsa)", "fl-fr-bl-br-fc-lfe-sl-sr"}, // not in lavc
{"7.1(wide)", "fl-fr-fc-lfe-bl-br-flc-frc"},
{"7.1(wide-side)", "fl-fr-fc-lfe-flc-frc-sl-sr"},
{"octagonal", "fl-fr-fc-bl-br-bc-sl-sr"},
{"downmix", "dl-dr"},
{0}
};
static const struct mp_chmap default_layouts[MP_NUM_CHANNELS + 1] = {
{0}, // empty
MP_CHMAP_INIT_MONO, // mono
MP_CHMAP2(FL, FR), // stereo
MP_CHMAP3(FL, FR, LFE), // 2.1
MP_CHMAP4(FL, FR, FC, BC), // 4.0
MP_CHMAP5(FL, FR, FC, BL, BR), // 5.0
MP_CHMAP6(FL, FR, FC, LFE, BL, BR), // 5.1
MP_CHMAP7(FL, FR, FC, LFE, BL, BR, BC), // 6.1
MP_CHMAP8(FL, FR, FC, LFE, BL, BR, SL, SR), // 7.1
};
// The channel order was lavc/waveex, but differs from lavc for 5, 6 and 8
// channels. 3 and 7 channels were likely undefined (no ALSA support).
static const char *mplayer_layouts[MP_NUM_CHANNELS + 1] = {
[1] = "mono",
[2] = "stereo",
[4] = "4.0",
[5] = "5.0(alsa)",
[6] = "5.1(alsa)",
[8] = "7.1(alsa)",
};
// Returns true if speakers are mapped uniquely, and there's at least 1 channel.
bool mp_chmap_is_valid(const struct mp_chmap *src)
{
bool mapped[MP_SPEAKER_ID_COUNT] = {0};
for (int n = 0; n < src->num; n++) {
int sp = src->speaker[n];
if (sp >= MP_SPEAKER_ID_COUNT || mapped[sp])
return false;
mapped[sp] = true;
}
return src->num > 0;
}
bool mp_chmap_is_empty(const struct mp_chmap *src)
{
return src->num == 0;
}
// Return true if the channel map defines the number of the channels only, and
// the channels have to meaning associated with them.
bool mp_chmap_is_unknown(const struct mp_chmap *src)
{
for (int n = 0; n < src->num; n++) {
int speaker = src->speaker[n];
if (speaker >= MP_SPEAKER_ID_UNKNOWN0 &&
speaker <= MP_SPEAKER_ID_UNKNOWN_LAST)
return true;
}
return false;
}
// Note: empty channel maps compare as equal. Invalid ones can equal too.
bool mp_chmap_equals(const struct mp_chmap *a, const struct mp_chmap *b)
{
if (a->num != b->num)
return false;
for (int n = 0; n < a->num; n++) {
if (a->speaker[n] != b->speaker[n])
return false;
}
return true;
}
// Whether they use the same speakers (even if in different order).
bool mp_chmap_equals_reordered(const struct mp_chmap *a, const struct mp_chmap *b)
{
struct mp_chmap t1 = *a, t2 = *b;
mp_chmap_reorder_norm(&t1);
mp_chmap_reorder_norm(&t2);
return mp_chmap_equals(&t1, &t2);
}
bool mp_chmap_is_compatible(const struct mp_chmap *a, const struct mp_chmap *b)
{
if (mp_chmap_equals(a, b))
return true;
if (a->num == b->num && (mp_chmap_is_unknown(a) || mp_chmap_is_unknown(b)))
return true;
return false;
}
bool mp_chmap_is_stereo(const struct mp_chmap *src)
{
static const struct mp_chmap stereo = MP_CHMAP_INIT_STEREO;
return mp_chmap_equals(src, &stereo);
}
static int comp_uint8(const void *a, const void *b)
{
return *(const uint8_t *)a - *(const uint8_t *)b;
}
// Reorder channels to normal order, with monotonically increasing speaker IDs.
// We define this order as the same order used with waveex.
void mp_chmap_reorder_norm(struct mp_chmap *map)
{
uint8_t *arr = &map->speaker[0];
qsort(arr, map->num, 1, comp_uint8);
}
// Set *dst to a standard layout with the given number of channels.
// If the number of channels is invalid, an invalid map is set, and
// mp_chmap_is_valid(dst) will return false.
void mp_chmap_from_channels(struct mp_chmap *dst, int num_channels)
{
if (num_channels < 0 || num_channels > MP_NUM_CHANNELS) {
*dst = (struct mp_chmap) {0};
} else {
*dst = default_layouts[num_channels];
}
}
// Try to do what mplayer/mplayer2/mpv did before channel layouts were
// introduced, i.e. get the old default channel order.
void mp_chmap_from_channels_alsa(struct mp_chmap *dst, int num_channels)
{
if (num_channels < 0 || num_channels > MP_NUM_CHANNELS) {
*dst = (struct mp_chmap) {0};
} else {
mp_chmap_from_str(dst, bstr0(mplayer_layouts[num_channels]));
if (!dst->num)
mp_chmap_from_channels(dst, num_channels);
}
}
// Set *dst to an unknown layout for the given numbers of channels.
// If the number of channels is invalid, an invalid map is set, and
// mp_chmap_is_valid(dst) will return false.
void mp_chmap_set_unknown(struct mp_chmap *dst, int num_channels)
{
if (num_channels < 0 || num_channels > MP_NUM_CHANNELS) {
*dst = (struct mp_chmap) {0};
} else {
dst->num = num_channels;
for (int n = 0; n < dst->num; n++)
dst->speaker[n] = MP_SPEAKER_ID_UNKNOWN0 + n;
}
}
// Return channel index of the given speaker, or -1.
static int mp_chmap_find_speaker(const struct mp_chmap *map, int speaker)
{
for (int n = 0; n < map->num; n++) {
if (map->speaker[n] == speaker)
return n;
}
return -1;
}
static void mp_chmap_remove_speaker(struct mp_chmap *map, int speaker)
{
int index = mp_chmap_find_speaker(map, speaker);
if (index >= 0) {
for (int n = index; n < map->num - 1; n++)
map->speaker[n] = map->speaker[n + 1];
map->num--;
}
}
// Some decoders output additional, redundant channels, which are usually
// useless and will mess up proper audio output channel handling.
// map: channel map from which the channels should be removed
// requested: if not NULL, and if it contains any of the "useless" channels,
// don't remove them (this is for convenience)
void mp_chmap_remove_useless_channels(struct mp_chmap *map,
const struct mp_chmap *requested)
{
if (requested &&
mp_chmap_find_speaker(requested, MP_SPEAKER_ID_DL) >= 0)
return;
if (map->num > 2) {
mp_chmap_remove_speaker(map, MP_SPEAKER_ID_DL);
mp_chmap_remove_speaker(map, MP_SPEAKER_ID_DR);
}
}
// Return the ffmpeg/libav channel layout as in <libavutil/channel_layout.h>.
// Warning: this ignores the order of the channels, and will return a channel
// mask even if the order is different from libavcodec's.
uint64_t mp_chmap_to_lavc_unchecked(const struct mp_chmap *src)
{
// lavc has no concept for unknown layouts yet, so pick a default
struct mp_chmap t = *src;
if (mp_chmap_is_unknown(&t))
mp_chmap_from_channels(&t, t.num);
uint64_t mask = 0;
for (int n = 0; n < t.num; n++)
mask |= 1ULL << t.speaker[n];
return mask;
}
// Return the ffmpeg/libav channel layout as in <libavutil/channel_layout.h>.
// Returns 0 if the channel order doesn't match lavc's or if it's invalid.
uint64_t mp_chmap_to_lavc(const struct mp_chmap *src)
{
if (!mp_chmap_is_lavc(src))
return 0;
return mp_chmap_to_lavc_unchecked(src);
}
// Set channel map from the ffmpeg/libav channel layout as in
// <libavutil/channel_layout.h>.
// If the number of channels exceed MP_NUM_CHANNELS, set dst to empty.
void mp_chmap_from_lavc(struct mp_chmap *dst, uint64_t src)
{
dst->num = 0;
for (int n = 0; n < 64; n++) {
if (src & (1ULL << n)) {
if (dst->num >= MP_NUM_CHANNELS) {
dst->num = 0;
return;
}
dst->speaker[dst->num] = n;
dst->num++;
}
}
}
bool mp_chmap_is_lavc(const struct mp_chmap *src)
{
if (!mp_chmap_is_valid(src))
return false;
if (mp_chmap_is_unknown(src))
return true;
// lavc's channel layout is a bit mask, and channels are always ordered
// from LSB to MSB speaker bits, so speaker IDs have to increase.
assert(src->num > 0);
for (int n = 1; n < src->num; n++) {
if (src->speaker[n - 1] >= src->speaker[n])
return false;
}
for (int n = 0; n < src->num; n++) {
if (src->speaker[n] >= 64)
return false;
}
return true;
}
void mp_chmap_reorder_to_lavc(struct mp_chmap *map)
{
if (!mp_chmap_is_valid(map))
return;
uint64_t mask = mp_chmap_to_lavc_unchecked(map);
mp_chmap_from_lavc(map, mask);
}
// Get reordering array for from->to reordering. from->to must have the same set
// of speakers (i.e. same number and speaker IDs, just different order). Then,
// for each speaker n, dst[n] will be set such that:
// to->speaker[dst[n]] = from->speaker[n]
// (dst[n] gives the source channel for destination channel n)
void mp_chmap_get_reorder(int dst[MP_NUM_CHANNELS], const struct mp_chmap *from,
const struct mp_chmap *to)
{
assert(from->num == to->num);
if (mp_chmap_is_unknown(from) || mp_chmap_is_unknown(to)) {
for (int n = 0; n < from->num; n++)
dst[n] = n;
return;
}
// Same set of speakers required
assert(mp_chmap_equals_reordered(from, to));
for (int n = 0; n < from->num; n++) {
int src = from->speaker[n];
dst[n] = -1;
for (int i = 0; i < to->num; i++) {
if (src == to->speaker[i]) {
dst[n] = i;
break;
}
}
assert(dst[n] != -1);
}
for (int n = 0; n < from->num; n++)
assert(to->speaker[dst[n]] == from->speaker[n]);
}
// Returns something like "fl-fr-fc". If there's a standard layout in lavc
// order, return that, e.g. "3.0" instead of "fl-fr-fc".
// Unassigned but valid speakers get names like "sp28".
char *mp_chmap_to_str(const struct mp_chmap *src)
{
char *res = talloc_strdup(NULL, "");
if (mp_chmap_is_unknown(src))
return talloc_asprintf_append_buffer(res, "unknown%d", src->num);
for (int n = 0; n < src->num; n++) {
int sp = src->speaker[n];
const char *s = sp < MP_SPEAKER_ID_COUNT ? speaker_names[sp][0] : NULL;
char buf[10];
if (!s) {
snprintf(buf, sizeof(buf), "sp%d", sp);
s = buf;
}
res = talloc_asprintf_append_buffer(res, "%s%s", n > 0 ? "-" : "", s);
}
// To standard layout name
for (int n = 0; std_layout_names[n][0]; n++) {
if (res && strcmp(res, std_layout_names[n][1]) == 0) {
talloc_free(res);
res = talloc_strdup(NULL, std_layout_names[n][0]);
break;
}
}
return res;
}
// If src can be parsed as channel map (as produced by mp_chmap_to_str()),
// return true and set *dst. Otherwise, return false and don't change *dst.
// Note: call mp_chmap_is_valid() to test whether the returned map is valid
// the map could be empty, or contain multiply mapped channels
bool mp_chmap_from_str(struct mp_chmap *dst, bstr src)
{
// Single number corresponds to mp_chmap_from_channels()
if (src.len > 0) {
bstr t = src;
bool unknown = bstr_eatstart0(&t, "unknown");
bstr rest;
long long count = bstrtoll(t, &rest, 10);
if (rest.len == 0) {
struct mp_chmap res;
if (unknown) {
mp_chmap_set_unknown(&res, count);
} else {
mp_chmap_from_channels(&res, count);
}
if (mp_chmap_is_valid(&res)) {
*dst = res;
return true;
}
}
}
// From standard layout name
for (int n = 0; std_layout_names[n][0]; n++) {
if (bstr_equals0(src, std_layout_names[n][0])) {
src = bstr0(std_layout_names[n][1]);
break;
}
}
// Explicit speaker list (separated by "-")
struct mp_chmap res = {0};
while (src.len) {
bstr s;
bstr_split_tok(src, "-", &s, &src);
int speaker = -1;
for (int n = 0; n < MP_SPEAKER_ID_COUNT; n++) {
const char *name = speaker_names[n][0];
if (name && bstr_equals0(s, name)) {
speaker = n;
break;
}
}
if (speaker < 0) {
if (bstr_eatstart0(&s, "sp")) {
long long sp = bstrtoll(s, &s, 0);
if (s.len == 0 && sp >= 0 && sp < MP_SPEAKER_ID_COUNT)
speaker = sp;
}
if (speaker < 0)
return false;
}
if (res.num >= MP_NUM_CHANNELS)
return false;
res.speaker[res.num] = speaker;
res.num++;
}
*dst = res;
return true;
}
void mp_chmap_print_help(int msgt, int msgl)
{
mp_msg(msgt, msgl, "Speakers:\n");
for (int n = 0; n < MP_SPEAKER_ID_COUNT; n++) {
if (speaker_names[n][0])
mp_msg(msgt, msgl, " %-16s (%s)\n",
speaker_names[n][0], speaker_names[n][1]);
}
mp_msg(msgt, msgl, "Standard layouts:\n");
for (int n = 0; std_layout_names[n][0]; n++) {
mp_msg(msgt, msgl, " %-16s (%s)\n",
std_layout_names[n][0], std_layout_names[n][1]);
}
for (int n = 0; n < MP_NUM_CHANNELS; n++)
mp_msg(msgt, msgl, " unknown%d\n", n);
}