[001/200] Add a new channel layout API

Message ID 20170526160238.82554-1-vittorio.giovara@gmail.com
State New
Headers show

Commit Message

Vittorio Giovara May 26, 2017, 4:02 p.m.
From: Anton Khirnov <anton@khirnov.net>

The new API is more extensible and allows for custom layouts.
More accurate information is exported, eg for decoders that do not
set a channel layout, lavc will not make one up for them.

Deprecate the old API working with just uint64_t bitmasks.

Expanded and completed by Vittorio Giovara <vittorio.giovara@gmail.com>.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
---
In this iteration:
 - change *map type to enum AVChannel
 - add uninit to copy
 - return int instead of enum AVChannel in case of errors

Vittorio

 libavutil/channel_layout.c | 387 +++++++++++++++++++++++++++++++++++++--------
 libavutil/channel_layout.h | 362 +++++++++++++++++++++++++++++++++++++++---
 libavutil/version.h        |   3 +
 3 files changed, 662 insertions(+), 90 deletions(-)

Patch

diff --git a/libavutil/channel_layout.c b/libavutil/channel_layout.c
index 41340ecdb6..285997446d 100644
--- a/libavutil/channel_layout.c
+++ b/libavutil/channel_layout.c
@@ -31,77 +31,90 @@ 
 #include "common.h"
 
 static const char * const 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 */
+    [AV_CHAN_FRONT_LEFT              ] = "FL",
+    [AV_CHAN_FRONT_RIGHT             ] = "FR",
+    [AV_CHAN_FRONT_CENTER            ] = "FC",
+    [AV_CHAN_LOW_FREQUENCY           ] = "LFE",
+    [AV_CHAN_BACK_LEFT               ] = "BL",
+    [AV_CHAN_BACK_RIGHT              ] = "BR",
+    [AV_CHAN_FRONT_LEFT_OF_CENTER    ] = "FLC",
+    [AV_CHAN_FRONT_RIGHT_OF_CENTER   ] = "FRC",
+    [AV_CHAN_BACK_CENTER             ] = "BC",
+    [AV_CHAN_SIDE_LEFT               ] = "SL",
+    [AV_CHAN_SIDE_RIGHT              ] = "SR",
+    [AV_CHAN_TOP_CENTER              ] = "TC",
+    [AV_CHAN_TOP_FRONT_LEFT          ] = "TFL",
+    [AV_CHAN_TOP_FRONT_CENTER        ] = "TFC",
+    [AV_CHAN_TOP_FRONT_RIGHT         ] = "TFR",
+    [AV_CHAN_TOP_BACK_LEFT           ] = "TBL",
+    [AV_CHAN_TOP_BACK_CENTER         ] = "TBC",
+    [AV_CHAN_TOP_BACK_RIGHT          ] = "TBR",
+    [AV_CHAN_STEREO_LEFT             ] = "DL",
+    [AV_CHAN_STEREO_RIGHT            ] = "DR",
+    [AV_CHAN_WIDE_LEFT               ] = "WL",
+    [AV_CHAN_WIDE_RIGHT              ] = "WR",
+    [AV_CHAN_SURROUND_DIRECT_LEFT    ] = "SDL",
+    [AV_CHAN_SURROUND_DIRECT_RIGHT   ] = "SDR",
+    [AV_CHAN_LOW_FREQUENCY_2         ] = "LFE2",
+    [AV_CHAN_SILENCE                 ] = "PAD",
 };
 
-static const char *get_channel_name(int channel_id)
+const char *av_channel_name(enum AVChannel channel_id)
 {
-    if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
-        return NULL;
+    if ((unsigned) channel_id >= FF_ARRAY_ELEMS(channel_names))
+        return "?";
     return channel_names[channel_id];
 }
 
+int av_channel_from_string(const char *str)
+{
+    int i;
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
+        if (channel_names[i] && !strcmp(str, channel_names[i])) {
+            return i;
+        }
+    }
+    return AVERROR(EINVAL);
+}
+
 static const struct {
     const char *name;
-    int         nb_channels;
-    uint64_t     layout;
+    AVChannelLayout layout;
 } channel_layout_map[] = {
-    { "mono",        1,  AV_CH_LAYOUT_MONO },
-    { "stereo",      2,  AV_CH_LAYOUT_STEREO },
-    { "stereo",      2,  AV_CH_LAYOUT_STEREO_DOWNMIX },
-    { "2.1",         3,  AV_CH_LAYOUT_2POINT1 },
-    { "3.0",         3,  AV_CH_LAYOUT_SURROUND },
-    { "3.0(back)",   3,  AV_CH_LAYOUT_2_1 },
-    { "3.1",         4,  AV_CH_LAYOUT_3POINT1 },
-    { "4.0",         4,  AV_CH_LAYOUT_4POINT0 },
-    { "quad",        4,  AV_CH_LAYOUT_QUAD },
-    { "quad(side)",  4,  AV_CH_LAYOUT_2_2 },
-    { "4.1",         5,  AV_CH_LAYOUT_4POINT1 },
-    { "5.0",         5,  AV_CH_LAYOUT_5POINT0 },
-    { "5.0",         5,  AV_CH_LAYOUT_5POINT0_BACK },
-    { "5.1",         6,  AV_CH_LAYOUT_5POINT1 },
-    { "5.1",         6,  AV_CH_LAYOUT_5POINT1_BACK },
-    { "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",         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 },
-    { "7.1(wide)",   8,  AV_CH_LAYOUT_7POINT1_WIDE_BACK },
-    { "octagonal",   8,  AV_CH_LAYOUT_OCTAGONAL },
-    { "hexadecagonal", 16, AV_CH_LAYOUT_HEXADECAGONAL },
-    { "downmix",     2,  AV_CH_LAYOUT_STEREO_DOWNMIX, },
+    { "mono",           AV_CHANNEL_LAYOUT_MONO                },
+    { "stereo",         AV_CHANNEL_LAYOUT_STEREO              },
+    { "stereo",         AV_CHANNEL_LAYOUT_STEREO_DOWNMIX      },
+    { "2.1",            AV_CHANNEL_LAYOUT_2POINT1             },
+    { "3.0",            AV_CHANNEL_LAYOUT_SURROUND            },
+    { "3.0(back)",      AV_CHANNEL_LAYOUT_2_1                 },
+    { "3.1",            AV_CHANNEL_LAYOUT_3POINT1             },
+    { "4.0",            AV_CHANNEL_LAYOUT_4POINT0             },
+    { "quad",           AV_CHANNEL_LAYOUT_QUAD                },
+    { "quad(side)",     AV_CHANNEL_LAYOUT_2_2                 },
+    { "4.1",            AV_CHANNEL_LAYOUT_4POINT1             },
+    { "5.0",            AV_CHANNEL_LAYOUT_5POINT0             },
+    { "5.0(back)",      AV_CHANNEL_LAYOUT_5POINT0_BACK        },
+    { "5.1",            AV_CHANNEL_LAYOUT_5POINT1             },
+    { "5.1(back)",      AV_CHANNEL_LAYOUT_5POINT1_BACK        },
+    { "6.0",            AV_CHANNEL_LAYOUT_6POINT0             },
+    { "6.0(front)",     AV_CHANNEL_LAYOUT_6POINT0_FRONT       },
+    { "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        },
+    { "7.1(wide-back)", AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK   },
+    { "octagonal",      AV_CHANNEL_LAYOUT_OCTAGONAL           },
+    { "hexadecagonal",  AV_CHANNEL_LAYOUT_HEXADECAGONAL       },
+    { "downmix",        AV_CHANNEL_LAYOUT_STEREO_DOWNMIX,     },
     { 0 }
 };
 
+#if FF_API_OLD_CHANNEL_LAYOUT
+FF_DISABLE_DEPRECATION_WARNINGS
 static uint64_t get_channel_layout_single(const char *name, int name_len)
 {
     int i;
@@ -111,7 +124,7 @@  static uint64_t get_channel_layout_single(const char *name, int name_len)
     for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map) - 1; 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;
+            return channel_layout_map[i].layout.u.mask;
     }
     for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
         if (channel_names[i] &&
@@ -153,8 +166,8 @@  void av_get_channel_layout_string(char *buf, int buf_size,
         nb_channels = av_get_channel_layout_nb_channels(channel_layout);
 
     for (i = 0; channel_layout_map[i].name; i++)
-        if (nb_channels    == channel_layout_map[i].nb_channels &&
-            channel_layout == channel_layout_map[i].layout) {
+        if (nb_channels    == channel_layout_map[i].layout.nb_channels &&
+            channel_layout == channel_layout_map[i].layout.u.mask) {
             av_strlcpy(buf, channel_layout_map[i].name, buf_size);
             return;
         }
@@ -165,7 +178,7 @@  void av_get_channel_layout_string(char *buf, int buf_size,
         av_strlcat(buf, " (", buf_size);
         for (i = 0, ch = 0; i < 64; i++) {
             if ((channel_layout & (UINT64_C(1) << i))) {
-                const char *name = get_channel_name(i);
+                const char *name = av_channel_name(i);
                 if (name) {
                     if (ch > 0)
                         av_strlcat(buf, "|", buf_size);
@@ -216,7 +229,7 @@  const char *av_get_channel_name(uint64_t channel)
         return NULL;
     for (i = 0; i < 64; i++)
         if ((1ULL<<i) & channel)
-            return get_channel_name(i);
+            return av_channel_name(i);
     return NULL;
 }
 
@@ -233,3 +246,249 @@  uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
     }
     return 0;
 }
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
+void av_channel_layout_from_mask(AVChannelLayout *channel_layout,
+                                 uint64_t mask)
+{
+    channel_layout->order       = AV_CHANNEL_ORDER_NATIVE;
+    channel_layout->nb_channels = av_popcount64(mask);
+    channel_layout->u.mask      = mask;
+}
+
+int av_channel_layout_from_string(AVChannelLayout *channel_layout,
+                                  const char *str)
+{
+    int i, channels;
+    const char *dup = str;
+    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;
+        }
+    }
+
+    /* channel names */
+    while (*dup) {
+        char *chname = av_get_token(&dup, "|");
+        if (!chname)
+            return AVERROR(ENOMEM);
+        if (*dup)
+            dup++; // skip separator
+        for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
+            if (channel_names[i] && !strcmp(chname, channel_names[i])) {
+                mask |= 1ULL << i;
+            }
+        }
+        av_free(chname);
+    }
+    if (mask) {
+        av_channel_layout_from_mask(channel_layout, mask);
+        return 0;
+    }
+
+    /* channel layout mask */
+    if (!strncmp(str, "0x", 2) && sscanf(str, "%llx", &mask) == 1) {
+        av_channel_layout_from_mask(channel_layout, mask);
+        return 0;
+    }
+
+    /* number of channels */
+    if (sscanf(str, "%d", &channels) == 1) {
+        av_channel_layout_default(channel_layout, channels);
+        return 0;
+    }
+
+    /* number of unordered channels */
+    if (sscanf(str, "%d channels", &channel_layout->nb_channels) == 1) {
+        channel_layout->order = AV_CHANNEL_ORDER_UNSPEC;
+        return 0;
+    }
+
+    return AVERROR_INVALIDDATA;
+}
+
+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(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;
+}
+
+char *av_channel_layout_describe(const AVChannelLayout *channel_layout)
+{
+    int i;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_NATIVE:
+        for (i = 0; channel_layout_map[i].name; i++)
+            if (channel_layout->u.mask == channel_layout_map[i].layout.u.mask)
+                return av_strdup(channel_layout_map[i].name);
+        // fall-through
+    case AV_CHANNEL_ORDER_CUSTOM: {
+        // max 4 bytes for channel name + a separator
+        int size = 5 * channel_layout->nb_channels + 1;
+        char *ret;
+
+        ret = av_mallocz(size);
+        if (!ret)
+            return NULL;
+
+        for (i = 0; i < channel_layout->nb_channels; i++) {
+            enum AVChannel ch = av_channel_layout_get_channel(channel_layout, i);
+            const char *ch_name = av_channel_name(ch);
+
+            if (i)
+                av_strlcat(ret, "|", size);
+            av_strlcat(ret, ch_name, size);
+        }
+        return ret;
+        }
+    case AV_CHANNEL_ORDER_UNSPEC: {
+        char buf[64];
+        snprintf(buf, sizeof(buf), "%d channels", channel_layout->nb_channels);
+        return av_strdup(buf);
+        }
+    default:
+        return NULL;
+    }
+}
+
+int av_channel_layout_get_channel(const AVChannelLayout *channel_layout, int idx)
+{
+    int i;
+
+    if (idx < 0 || idx >= channel_layout->nb_channels)
+        return AVERROR(EINVAL);
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_CUSTOM:
+        return channel_layout->u.map[idx];
+    case AV_CHANNEL_ORDER_NATIVE:
+        for (i = 0; i < 64; i++) {
+            if ((1ULL << i) & channel_layout->u.mask && !idx--)
+                return i;
+        }
+    default:
+        return AVERROR(EINVAL);
+    }
+}
+
+int av_channel_layout_channel_index(const AVChannelLayout *channel_layout,
+                                    enum AVChannel channel)
+{
+    int i;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_CUSTOM:
+        for (i = 0; i < channel_layout->nb_channels; i++)
+            if (channel_layout->u.map[i] == channel)
+                return i;
+        return AVERROR(EINVAL);
+    case AV_CHANNEL_ORDER_NATIVE: {
+        uint64_t mask = channel_layout->u.mask;
+        if (!(mask & (1ULL << channel)))
+            return AVERROR(EINVAL);
+        mask &= (1ULL << channel) - 1;
+        return av_popcount64(mask);
+        }
+    default:
+        return AVERROR(EINVAL);
+    }
+}
+
+int av_channel_layout_check(const AVChannelLayout *channel_layout)
+{
+    if (!channel_layout || 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:
+        return !!channel_layout->u.map;
+    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_CUSTOM &&
+        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_get_channel(chl,  i) !=
+            av_channel_layout_get_channel(chl1, i))
+            return 1;
+    return 0;
+}
+
+void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels)
+{
+    switch (nb_channels) {
+    case 1: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;     break;
+    case 2: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;   break;
+    case 3: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_SURROUND; break;
+    case 4: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD;     break;
+    case 5: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT0;  break;
+    case 6: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT1;  break;
+    case 7: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_6POINT1;  break;
+    case 8: *ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_7POINT1;  break;
+    default:
+        ch_layout->order       = AV_CHANNEL_ORDER_UNSPEC;
+        ch_layout->nb_channels = nb_channels;
+    }
+}
+
+uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
+                                  uint64_t mask)
+{
+    uint64_t ret = 0;
+    int i;
+
+    if (channel_layout->order == AV_CHANNEL_ORDER_NATIVE)
+        return channel_layout->u.mask & mask;
+
+    for (i = 0; i < 64; i++)
+        if (mask & (1ULL << i) && av_channel_layout_channel_index(channel_layout, i) >= 0)
+            ret |= (1ULL << i);
+
+    return ret;
+}
diff --git a/libavutil/channel_layout.h b/libavutil/channel_layout.h
index 5bd0c2ce6e..2604ad1537 100644
--- a/libavutil/channel_layout.h
+++ b/libavutil/channel_layout.h
@@ -24,6 +24,9 @@ 
 
 #include <stdint.h>
 
+#include "version.h"
+#include "attributes.h"
+
 /**
  * @file
  * audio channel layout utility functions
@@ -34,40 +37,99 @@ 
  * @{
  */
 
+enum AVChannel {
+    AV_CHAN_FRONT_LEFT,
+    AV_CHAN_FRONT_RIGHT,
+    AV_CHAN_FRONT_CENTER,
+    AV_CHAN_LOW_FREQUENCY,
+    AV_CHAN_BACK_LEFT,
+    AV_CHAN_BACK_RIGHT,
+    AV_CHAN_FRONT_LEFT_OF_CENTER,
+    AV_CHAN_FRONT_RIGHT_OF_CENTER,
+    AV_CHAN_BACK_CENTER,
+    AV_CHAN_SIDE_LEFT,
+    AV_CHAN_SIDE_RIGHT,
+    AV_CHAN_TOP_CENTER,
+    AV_CHAN_TOP_FRONT_LEFT,
+    AV_CHAN_TOP_FRONT_CENTER,
+    AV_CHAN_TOP_FRONT_RIGHT,
+    AV_CHAN_TOP_BACK_LEFT,
+    AV_CHAN_TOP_BACK_CENTER,
+    AV_CHAN_TOP_BACK_RIGHT,
+    /** Stereo downmix. */
+    AV_CHAN_STEREO_LEFT = 29,
+    /** See above. */
+    AV_CHAN_STEREO_RIGHT,
+    AV_CHAN_WIDE_LEFT,
+    AV_CHAN_WIDE_RIGHT,
+    AV_CHAN_SURROUND_DIRECT_LEFT,
+    AV_CHAN_SURROUND_DIRECT_RIGHT,
+    AV_CHAN_LOW_FREQUENCY_2,
+
+    /** Channel is empty can be safely skipped. */
+    AV_CHAN_SILENCE = 64,
+};
+
+enum AVChannelOrder {
+    /**
+     * The native channel order, i.e. the channels are in the same order in
+     * which they are defined in the AVChannel enum. This supports up to 63
+     * different channels.
+     */
+    AV_CHANNEL_ORDER_NATIVE,
+    /**
+     * The channel order does not correspond to any other predefined order and
+     * is stored as an explicit map. For example, this could be used to support
+     * layouts with 64 or more channels, or with channels that could be skipped.
+     */
+    AV_CHANNEL_ORDER_CUSTOM,
+    /**
+     * Only the channel count is specified, without any further information
+     * about the channel order.
+     */
+    AV_CHANNEL_ORDER_UNSPEC,
+};
+
+
 /**
  * @defgroup channel_masks Audio channel masks
  * @{
  */
-#define AV_CH_FRONT_LEFT             0x00000001
-#define AV_CH_FRONT_RIGHT            0x00000002
-#define AV_CH_FRONT_CENTER           0x00000004
-#define AV_CH_LOW_FREQUENCY          0x00000008
-#define AV_CH_BACK_LEFT              0x00000010
-#define AV_CH_BACK_RIGHT             0x00000020
-#define AV_CH_FRONT_LEFT_OF_CENTER   0x00000040
-#define AV_CH_FRONT_RIGHT_OF_CENTER  0x00000080
-#define AV_CH_BACK_CENTER            0x00000100
-#define AV_CH_SIDE_LEFT              0x00000200
-#define AV_CH_SIDE_RIGHT             0x00000400
-#define AV_CH_TOP_CENTER             0x00000800
-#define AV_CH_TOP_FRONT_LEFT         0x00001000
-#define AV_CH_TOP_FRONT_CENTER       0x00002000
-#define AV_CH_TOP_FRONT_RIGHT        0x00004000
-#define AV_CH_TOP_BACK_LEFT          0x00008000
-#define AV_CH_TOP_BACK_CENTER        0x00010000
-#define AV_CH_TOP_BACK_RIGHT         0x00020000
-#define AV_CH_STEREO_LEFT            0x20000000  ///< Stereo downmix.
-#define AV_CH_STEREO_RIGHT           0x40000000  ///< See AV_CH_STEREO_LEFT.
-#define AV_CH_WIDE_LEFT              0x0000000080000000ULL
-#define AV_CH_WIDE_RIGHT             0x0000000100000000ULL
-#define AV_CH_SURROUND_DIRECT_LEFT   0x0000000200000000ULL
-#define AV_CH_SURROUND_DIRECT_RIGHT  0x0000000400000000ULL
-#define AV_CH_LOW_FREQUENCY_2        0x0000000800000000ULL
+#define AV_CH_FRONT_LEFT             (1ULL << AV_CHAN_FRONT_LEFT           )
+#define AV_CH_FRONT_RIGHT            (1ULL << AV_CHAN_FRONT_RIGHT          )
+#define AV_CH_FRONT_CENTER           (1ULL << AV_CHAN_FRONT_CENTER         )
+#define AV_CH_LOW_FREQUENCY          (1ULL << AV_CHAN_LOW_FREQUENCY        )
+#define AV_CH_BACK_LEFT              (1ULL << AV_CHAN_BACK_LEFT            )
+#define AV_CH_BACK_RIGHT             (1ULL << AV_CHAN_BACK_RIGHT           )
+#define AV_CH_FRONT_LEFT_OF_CENTER   (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
+#define AV_CH_FRONT_RIGHT_OF_CENTER  (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
+#define AV_CH_BACK_CENTER            (1ULL << AV_CHAN_BACK_CENTER          )
+#define AV_CH_SIDE_LEFT              (1ULL << AV_CHAN_SIDE_LEFT            )
+#define AV_CH_SIDE_RIGHT             (1ULL << AV_CHAN_SIDE_RIGHT           )
+#define AV_CH_TOP_CENTER             (1ULL << AV_CHAN_TOP_CENTER           )
+#define AV_CH_TOP_FRONT_LEFT         (1ULL << AV_CHAN_TOP_FRONT_LEFT       )
+#define AV_CH_TOP_FRONT_CENTER       (1ULL << AV_CHAN_TOP_FRONT_CENTER     )
+#define AV_CH_TOP_FRONT_RIGHT        (1ULL << AV_CHAN_TOP_FRONT_RIGHT      )
+#define AV_CH_TOP_BACK_LEFT          (1ULL << AV_CHAN_TOP_BACK_LEFT        )
+#define AV_CH_TOP_BACK_CENTER        (1ULL << AV_CHAN_TOP_BACK_CENTER      )
+#define AV_CH_TOP_BACK_RIGHT         (1ULL << AV_CHAN_TOP_BACK_RIGHT       )
+#define AV_CH_STEREO_LEFT            (1ULL << AV_CHAN_STEREO_LEFT          )
+#define AV_CH_STEREO_RIGHT           (1ULL << AV_CHAN_STEREO_RIGHT         )
+#define AV_CH_WIDE_LEFT              (1ULL << AV_CHAN_WIDE_LEFT            )
+#define AV_CH_WIDE_RIGHT             (1ULL << AV_CHAN_WIDE_RIGHT           )
+#define AV_CH_SURROUND_DIRECT_LEFT   (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
+#define AV_CH_SURROUND_DIRECT_RIGHT  (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
+#define AV_CH_LOW_FREQUENCY_2        (1ULL << AV_CHAN_LOW_FREQUENCY_2      )
 
+#if FF_API_OLD_CHANNEL_LAYOUT
 /** Channel mask value used for AVCodecContext.request_channel_layout
     to indicate that the user requests the channel order of the decoder output
-    to be the native codec channel order. */
+    to be the native codec channel order.
+    @deprecated channel order is now indicated in a special field in
+                AVChannelLayout
+    */
 #define AV_CH_LAYOUT_NATIVE          0x8000000000000000ULL
+#endif
 
 /**
  * @}
@@ -119,6 +181,123 @@  enum AVMatrixEncoding {
  */
 
 /**
+ * An AVChannelLayout holds information about the channel layout of audio data.
+ *
+ * A channel layout here is defined as a set of channels ordered in a specific
+ * way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
+ * AVChannelLayout carries only the channel count).
+ *
+ * Unlike most structures in Libav, sizeof(AVChannelLayout) is a part of the
+ * public ABI and may be used by the caller. E.g. it may be allocated on stack.
+ * No new fields may be added to it without a major version bump.
+ *
+ * An AVChannelLayout can be constructed using the convenience function
+ * av_channel_layout_from_mask() / av_channel_layout_from_string(), or it can be
+ * built manually by the caller.
+ */
+typedef struct AVChannelLayout {
+    /**
+     * Channel order used in this layout.
+     */
+    enum AVChannelOrder order;
+
+    /**
+     * Number of channels in this layout. Mandatory field.
+     */
+    int nb_channels;
+
+    /**
+     * Details about which channels are present in this layout.
+     * For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
+     * used.
+     */
+    union {
+        /**
+         * This member must be used for AV_CHANNEL_ORDER_NATIVE.
+         * It is a bitmask, where the position of each set bit means that the
+         * AVChannel with the corresponding value is present.
+         *
+         * I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
+         * is present in the layout. Otherwise it is not present.
+         *
+         * @note when a channel layout using a bitmask is constructed or
+         * modified manually (i.e.  not using any of the av_channel_layout_*
+         * functions), the code doing it must ensure that the number of set bits
+         * is equal to nb_channels.
+         */
+        uint64_t mask;
+        /**
+         * This member must be used when the channel order is
+         * AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
+         * element signalling the presend of the AVChannel with the
+         * corresponding value.
+         *
+         * I.e. when map[i] is equal to AV_CHAN_FOO, then AV_CH_FOO is the i-th
+         * channel in the audio data.
+         */
+        enum AVChannel *map;
+    } u;
+} AVChannelLayout;
+
+#define AV_CHANNEL_LAYOUT_MONO \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 1,  .u = { .mask = AV_CH_LAYOUT_MONO }}
+#define AV_CHANNEL_LAYOUT_STEREO \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 2,  .u = { .mask = AV_CH_LAYOUT_STEREO }}
+#define AV_CHANNEL_LAYOUT_2POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 3,  .u = { .mask = AV_CH_LAYOUT_2POINT1 }}
+#define AV_CHANNEL_LAYOUT_2_1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 3,  .u = { .mask = AV_CH_LAYOUT_2_1 }}
+#define AV_CHANNEL_LAYOUT_SURROUND \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 3,  .u = { .mask = AV_CH_LAYOUT_SURROUND }}
+#define AV_CHANNEL_LAYOUT_3POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 4,  .u = { .mask = AV_CH_LAYOUT_3POINT1 }}
+#define AV_CHANNEL_LAYOUT_4POINT0 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 4,  .u = { .mask = AV_CH_LAYOUT_4POINT0 }}
+#define AV_CHANNEL_LAYOUT_4POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 5,  .u = { .mask = AV_CH_LAYOUT_4POINT1 }}
+#define AV_CHANNEL_LAYOUT_2_2 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 4,  .u = { .mask = AV_CH_LAYOUT_2_2 }}
+#define AV_CHANNEL_LAYOUT_QUAD \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 4,  .u = { .mask = AV_CH_LAYOUT_QUAD }}
+#define AV_CHANNEL_LAYOUT_5POINT0 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 5,  .u = { .mask = AV_CH_LAYOUT_5POINT0 }}
+#define AV_CHANNEL_LAYOUT_5POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 6,  .u = { .mask = AV_CH_LAYOUT_5POINT1 }}
+#define AV_CHANNEL_LAYOUT_5POINT0_BACK \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 5,  .u = { .mask = AV_CH_LAYOUT_5POINT0_BACK }}
+#define AV_CHANNEL_LAYOUT_5POINT1_BACK \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 6,  .u = { .mask = AV_CH_LAYOUT_5POINT1_BACK }}
+#define AV_CHANNEL_LAYOUT_6POINT0 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 6,  .u = { .mask = AV_CH_LAYOUT_6POINT0 }}
+#define AV_CHANNEL_LAYOUT_6POINT0_FRONT \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 6,  .u = { .mask = AV_CH_LAYOUT_6POINT0_FRONT }}
+#define AV_CHANNEL_LAYOUT_HEXAGONAL \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 6,  .u = { .mask = AV_CH_LAYOUT_HEXAGONAL }}
+#define AV_CHANNEL_LAYOUT_6POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 7,  .u = { .mask = AV_CH_LAYOUT_6POINT1 }}
+#define AV_CHANNEL_LAYOUT_6POINT1_BACK \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 7,  .u = { .mask = AV_CH_LAYOUT_6POINT1_BACK }}
+#define AV_CHANNEL_LAYOUT_6POINT1_FRONT \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 7,  .u = { .mask = AV_CH_LAYOUT_6POINT1_FRONT }}
+#define AV_CHANNEL_LAYOUT_7POINT0 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 7,  .u = { .mask = AV_CH_LAYOUT_7POINT0 }}
+#define AV_CHANNEL_LAYOUT_7POINT0_FRONT \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 7,  .u = { .mask = AV_CH_LAYOUT_7POINT0_FRONT }}
+#define AV_CHANNEL_LAYOUT_7POINT1 \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 8,  .u = { .mask = AV_CH_LAYOUT_7POINT1 }}
+#define AV_CHANNEL_LAYOUT_7POINT1_WIDE \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 8,  .u = { .mask = AV_CH_LAYOUT_7POINT1_WIDE }}
+#define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 8,  .u = { .mask = AV_CH_LAYOUT_7POINT1_WIDE_BACK }}
+#define AV_CHANNEL_LAYOUT_OCTAGONAL \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 8,  .u = { .mask = AV_CH_LAYOUT_OCTAGONAL }}
+#define AV_CHANNEL_LAYOUT_HEXADECAGONAL \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 16, .u = { .mask = AV_CH_LAYOUT_HEXAGONAL }}
+#define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = 2,  .u = { .mask = AV_CH_LAYOUT_STEREO_DOWNMIX }}
+
+#if FF_API_OLD_CHANNEL_LAYOUT
+/**
  * Return a channel layout id that matches name, or 0 if no match is found.
  *
  * name can be one or several of the following notations,
@@ -134,7 +313,10 @@  enum AVMatrixEncoding {
  *   AV_CH_* macros).
  *
  * Example: "stereo+FC" = "2+FC" = "2c+1c" = "0x7"
+ *
+ * @deprecated use av_channel_layout_from_string()
  */
+attribute_deprecated
 uint64_t av_get_channel_layout(const char *name);
 
 /**
@@ -143,17 +325,24 @@  uint64_t av_get_channel_layout(const char *name);
  *
  * @param buf put here the string containing the channel layout
  * @param buf_size size in bytes of the buffer
+ * @deprecated use av_channel_layout_describe()
  */
+attribute_deprecated
 void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout);
 
 /**
  * Return the number of channels in the channel layout.
+ * @deprecated use AVChannelLayout.nb_channels
  */
+attribute_deprecated
 int av_get_channel_layout_nb_channels(uint64_t channel_layout);
 
 /**
  * Return default channel layout for a given number of channels.
+ *
+ * @deprecated use av_channel_layout_default()
  */
+attribute_deprecated
 uint64_t av_get_default_channel_layout(int nb_channels);
 
 /**
@@ -164,21 +353,142 @@  uint64_t av_get_default_channel_layout(int nb_channels);
  *
  * @return index of channel in channel_layout on success, a negative AVERROR
  *         on error.
+ *
+ * @deprecated use av_channel_layout_channel_index()
  */
+attribute_deprecated
 int av_get_channel_layout_channel_index(uint64_t channel_layout,
                                         uint64_t channel);
 
 /**
  * Get the channel with the given index in channel_layout.
+ * @deprecated use av_channel_layout_get_channel()
  */
+attribute_deprecated
 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index);
 
 /**
  * Get the name of a given channel.
  *
  * @return channel name on success, NULL on error.
+ *
+ * @deprecated use av_channel_name()
  */
+attribute_deprecated
 const char *av_get_channel_name(uint64_t channel);
+#endif
+
+/**
+ * @return a string describing a given channel.
+ */
+const char *av_channel_name(enum AVChannel channel);
+
+/**
+ * @return a channel described by the given string.
+ */
+int av_channel_from_string(const char *name);
+
+/**
+ * Initialize a native channel layout from a bitmask indicating which channels
+ * are present.
+ */
+void av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
+
+/**
+ * Initialize a channel layout from a given string description.
+ * The input string can be represented by:
+ *  - the formal channel layout name (returned by av_channel_layout_describe())
+ *  - single or multiple channel names (returned by av_channel_name()
+ *    or concatenated with "|")
+ *  - a hexadecimal value of a channel layout (eg. "0x4")
+ *  - the number of channels with default layout (eg. "5")
+ *  - the number of unordered channels (eg. "4 channels")
+ *
+ * @param channel_layout input channel layout
+ * @param str string describing the channel layout
+ * @return 0 channel layout was detected, AVERROR_INVALIDATATA otherwise
+ */
+int av_channel_layout_from_string(AVChannelLayout *channel_layout,
+                                  const char *str);
+
+/**
+ * Get the default channel layout for a given number of channels.
+ */
+void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
+
+/**
+ * Free any allocated data in the channel layout and reset the channel
+ * count to 0.
+ */
+void av_channel_layout_uninit(AVChannelLayout *channel_layout);
+
+/**
+ * Make a copy of a channel layout. This differs from just assigning src to dst
+ * in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
+ *
+ * @param dst destination channel layout
+ * @param src source channel layout
+ * @return 0 on success, a negative AVERROR on error.
+ */
+int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src);
+
+/**
+ * @return a string describing channel_layout or NULL on failure in the same
+ *         format that is accepted by av_channel_layout_from_string(). The
+ *         returned string allocated with av_malloc() and must be freed by the
+ *         caller with av_free().
+ */
+char *av_channel_layout_describe(const AVChannelLayout *channel_layout);
+
+/**
+ * Get the channel with the given index in a channel layout.
+ *
+ * @return channel with the index idx in channel_layout on success or a negative
+ *                 AVERROR on failure (if idx is not valid or the channel order
+ *                 is unspecified)
+ */
+int av_channel_layout_get_channel(const AVChannelLayout *channel_layout, int idx);
+
+/**
+ * Get the index of a given channel in a channel layout.
+ *
+ * @return index of channel in channel_layout on success or a negative number if
+ *         channel is not present in channel_layout.
+ */
+int av_channel_layout_channel_index(const AVChannelLayout *channel_layout,
+                                    enum AVChannel channel);
+
+/**
+ * Find out what channels from a given set are present in a channel layout,
+ * without regard for their positions.
+ *
+ * @param mask a combination of AV_CH_* representing a set of channels
+ * @return a bitfield representing all the channels from mask that are present
+ *         in channel_layout
+ */
+uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
+                                  uint64_t mask);
+
+/**
+ * Check whether a channel layout is valid, i.e. can possibly describe audio
+ * data.
+ *
+ * @return 1 if channel_layout is valid, 0 otherwise.
+ */
+int av_channel_layout_check(const AVChannelLayout *channel_layout);
+
+/**
+ * Check whether two channel layouts are semantically the same, i.e. the same
+ * channels are present on the same positions in both.
+ *
+ * If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
+ * not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
+ * they are considered equal iff the channel counts are the same in both.
+ *
+ * @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
+ * AVERROR code if one or both are invalid.
+ */
+int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1);
 
 /**
  * @}
diff --git a/libavutil/version.h b/libavutil/version.h
index 7779755870..199a88433d 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -96,6 +96,9 @@ 
 #ifndef FF_API_CRYPTO_SIZE_T
 #define FF_API_CRYPTO_SIZE_T            (LIBAVUTIL_VERSION_MAJOR < 57)
 #endif
+#ifndef FF_API_OLD_CHANNEL_LAYOUT
+#define FF_API_OLD_CHANNEL_LAYOUT       (LIBAVUTIL_VERSION_MAJOR < 57)
+#endif
 
 
 /**