audio: add channel map API

Unused, will be used in the following commits.

Let chmap.h define the number of maximum channels, because that is most
convenient.

1 files changed, 133 insertions, 0 deletions

diff --git a/audio/chmap.h b/audio/chmap.h
new file mode 100644
index 0000000000..9ab97ac8ba
--- /dev/null
+++ b/audio/chmap.h
@@ -0,0 +1,133 @@
+/*
+ * 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/>.
+ */
+
+#ifndef MP_CHMAP_H
+#define MP_CHMAP_H
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include "core/bstr.h"
+
+#define MP_NUM_CHANNELS 8
+
+// Speaker a channel can be assigned to.
+// This corresponds to WAVEFORMATEXTENSIBLE channel mask bit indexes.
+// E.g. channel_mask = (1 << MP_SPEAKER_ID_FL) | ...
+enum {
+    // Official WAVEFORMATEXTENSIBLE (shortened names)
+    MP_SPEAKER_ID_FL = 0,       // FRONT_LEFT
+    MP_SPEAKER_ID_FR,           // FRONT_RIGHT
+    MP_SPEAKER_ID_FC,           // FRONT_CENTER
+    MP_SPEAKER_ID_LFE,          // LOW_FREQUENCY
+    MP_SPEAKER_ID_BL,           // BACK_LEFT
+    MP_SPEAKER_ID_BR,           // BACK_RIGHT
+    MP_SPEAKER_ID_FLC,          // FRONT_LEFT_OF_CENTER
+    MP_SPEAKER_ID_FRC,          // FRONT_RIGHT_OF_CENTER
+    MP_SPEAKER_ID_BC,           // BACK_CENTER
+    MP_SPEAKER_ID_SL,           // SIDE_LEFT
+    MP_SPEAKER_ID_SR,           // SIDE_RIGHT
+    MP_SPEAKER_ID_TC,           // TOP_CENTER
+    MP_SPEAKER_ID_TFL,          // TOP_FRONT_LEFT
+    MP_SPEAKER_ID_TFC,          // TOP_FRONT_CENTER
+    MP_SPEAKER_ID_TFR,          // TOP_FRONT_RIGHT
+    MP_SPEAKER_ID_TBL,          // TOP_BACK_LEFT
+    MP_SPEAKER_ID_TBC,          // TOP_BACK_CENTER
+    MP_SPEAKER_ID_TBR,          // TOP_BACK_RIGHT
+     // Inofficial/libav* extensions
+    MP_SPEAKER_ID_DL = 29,      // STEREO_LEFT (stereo downmix special speakers)
+    MP_SPEAKER_ID_DR,           // STEREO_RIGHT
+    MP_SPEAKER_ID_WL,           // WIDE_LEFT
+    MP_SPEAKER_ID_WR,           // WIDE_RIGHT
+    MP_SPEAKER_ID_SDL,          // SURROUND_DIRECT_LEFT
+    MP_SPEAKER_ID_SDR,          // SURROUND_DIRECT_RIGHT
+    MP_SPEAKER_ID_LFE2,         // LOW_FREQUENCY_2
+
+    // Special mpv-specific speaker entries reserved for channels which have no
+    // known meaning.
+    MP_SPEAKER_ID_UNKNOWN0 = 64,
+    MP_SPEAKER_ID_UNKNOWN_LAST = MP_SPEAKER_ID_UNKNOWN0 + MP_NUM_CHANNELS - 1,
+
+    // Including the unassigned IDs in between. This is not a valid ID anymore.
+    MP_SPEAKER_ID_COUNT,
+};
+
+struct mp_chmap {
+    uint8_t num; // number of channels
+    // Given a channel n, speaker[n] is the speaker ID driven by that channel.
+    // Entries after speaker[num - 1] are undefined.
+    uint8_t speaker[MP_NUM_CHANNELS];
+};
+
+#define MP_SP(speaker) MP_SPEAKER_ID_ ## speaker
+
+#define MP_CHMAP2(a, b) \
+    {2, {MP_SP(a), MP_SP(b)}}
+#define MP_CHMAP3(a, b, c) \
+    {3, {MP_SP(a), MP_SP(b), MP_SP(c)}}
+#define MP_CHMAP4(a, b, c, d) \
+    {4, {MP_SP(a), MP_SP(b), MP_SP(c), MP_SP(d)}}
+#define MP_CHMAP5(a, b, c, d, e) \
+    {5, {MP_SP(a), MP_SP(b), MP_SP(c), MP_SP(d), MP_SP(e)}}
+#define MP_CHMAP6(a, b, c, d, e, f) \
+    {6, {MP_SP(a), MP_SP(b), MP_SP(c), MP_SP(d), MP_SP(e), MP_SP(f)}}
+#define MP_CHMAP7(a, b, c, d, e, f, g) \
+    {7, {MP_SP(a), MP_SP(b), MP_SP(c), MP_SP(d), MP_SP(e), MP_SP(f), MP_SP(g)}}
+#define MP_CHMAP8(a, b, c, d, e, f, g, h) \
+    {8, {MP_SP(a), MP_SP(b), MP_SP(c), MP_SP(d), MP_SP(e), MP_SP(f), MP_SP(g), MP_SP(h)}}
+
+#define MP_CHMAP_INIT_MONO {1, {MP_SPEAKER_ID_FC}}
+#define MP_CHMAP_INIT_STEREO MP_CHMAP2(FL, FR)
+
+bool mp_chmap_is_valid(const struct mp_chmap *src);
+bool mp_chmap_is_empty(const struct mp_chmap *src);
+bool mp_chmap_is_unknown(const struct mp_chmap *src);
+bool mp_chmap_equals(const struct mp_chmap *a, const struct mp_chmap *b);
+bool mp_chmap_equals_reordered(const struct mp_chmap *a, const struct mp_chmap *b);
+bool mp_chmap_is_compatible(const struct mp_chmap *a, const struct mp_chmap *b);
+bool mp_chmap_is_stereo(const struct mp_chmap *src);
+
+void mp_chmap_reorder_norm(struct mp_chmap *map);
+
+void mp_chmap_from_channels(struct mp_chmap *dst, int num_channels);
+void mp_chmap_set_unknown(struct mp_chmap *dst, int num_channels);
+
+void mp_chmap_remove_useless_channels(struct mp_chmap *map,
+                                      const struct mp_chmap *requested);
+
+uint64_t mp_chmap_to_lavc(const struct mp_chmap *src);
+uint64_t mp_chmap_to_lavc_unchecked(const struct mp_chmap *src);
+void mp_chmap_from_lavc(struct mp_chmap *dst, uint64_t src);
+
+bool mp_chmap_is_lavc(const struct mp_chmap *src);
+void mp_chmap_reorder_to_lavc(struct mp_chmap *map);
+
+void mp_chmap_reorder_to_alsa(struct mp_chmap *map);
+
+void mp_chmap_get_reorder(int dst[MP_NUM_CHANNELS], const struct mp_chmap *from,
+                          const struct mp_chmap *to);
+
+char *mp_chmap_to_str(const struct mp_chmap *src);
+bool mp_chmap_from_str(struct mp_chmap *dst, bstr src);
+void mp_chmap_print_help(int msgt, int msgl);
+
+// Use these to avoid chaos in case lavc's definition should diverge from MS.
+#define mp_chmap_to_waveext mp_chmap_to_lavc
+#define mp_chmap_from_waveext mp_chmap_from_lavc
+#define mp_chmap_is_waveext mp_chmap_is_lavc
+#define mp_chmap_reorder_to_waveext mp_chmap_reorder_to_lavc
+
+#endif