Adding upstream version 0.37.0.upstream/0.37.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 719 insertions, 0 deletions

diff --git a/audio/out/ao.c b/audio/out/ao.c
new file mode 100644
index 0000000..a5aa3a9
--- /dev/null
+++ b/audio/out/ao.c
@@ -0,0 +1,719 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv 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.
+ *
+ * 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+
+#include "mpv_talloc.h"
+
+#include "config.h"
+#include "ao.h"
+#include "internal.h"
+#include "audio/format.h"
+
+#include "options/options.h"
+#include "options/m_config_frontend.h"
+#include "osdep/endian.h"
+#include "common/msg.h"
+#include "common/common.h"
+#include "common/global.h"
+
+extern const struct ao_driver audio_out_oss;
+extern const struct ao_driver audio_out_audiotrack;
+extern const struct ao_driver audio_out_audiounit;
+extern const struct ao_driver audio_out_coreaudio;
+extern const struct ao_driver audio_out_coreaudio_exclusive;
+extern const struct ao_driver audio_out_rsound;
+extern const struct ao_driver audio_out_pipewire;
+extern const struct ao_driver audio_out_sndio;
+extern const struct ao_driver audio_out_pulse;
+extern const struct ao_driver audio_out_jack;
+extern const struct ao_driver audio_out_openal;
+extern const struct ao_driver audio_out_opensles;
+extern const struct ao_driver audio_out_null;
+extern const struct ao_driver audio_out_alsa;
+extern const struct ao_driver audio_out_wasapi;
+extern const struct ao_driver audio_out_pcm;
+extern const struct ao_driver audio_out_lavc;
+extern const struct ao_driver audio_out_sdl;
+
+static const struct ao_driver * const audio_out_drivers[] = {
+// native:
+#if HAVE_ANDROID
+    &audio_out_audiotrack,
+#endif
+#if HAVE_AUDIOUNIT
+    &audio_out_audiounit,
+#endif
+#if HAVE_COREAUDIO
+    &audio_out_coreaudio,
+#endif
+#if HAVE_PIPEWIRE
+    &audio_out_pipewire,
+#endif
+#if HAVE_PULSE
+    &audio_out_pulse,
+#endif
+#if HAVE_ALSA
+    &audio_out_alsa,
+#endif
+#if HAVE_WASAPI
+    &audio_out_wasapi,
+#endif
+#if HAVE_OSS_AUDIO
+    &audio_out_oss,
+#endif
+    // wrappers:
+#if HAVE_JACK
+    &audio_out_jack,
+#endif
+#if HAVE_OPENAL
+    &audio_out_openal,
+#endif
+#if HAVE_OPENSLES
+    &audio_out_opensles,
+#endif
+#if HAVE_SDL2_AUDIO
+    &audio_out_sdl,
+#endif
+#if HAVE_SNDIO
+    &audio_out_sndio,
+#endif
+    &audio_out_null,
+#if HAVE_COREAUDIO
+    &audio_out_coreaudio_exclusive,
+#endif
+    &audio_out_pcm,
+    &audio_out_lavc,
+};
+
+static bool get_desc(struct m_obj_desc *dst, int index)
+{
+    if (index >= MP_ARRAY_SIZE(audio_out_drivers))
+        return false;
+    const struct ao_driver *ao = audio_out_drivers[index];
+    *dst = (struct m_obj_desc) {
+        .name = ao->name,
+        .description = ao->description,
+        .priv_size = ao->priv_size,
+        .priv_defaults = ao->priv_defaults,
+        .options = ao->options,
+        .options_prefix = ao->options_prefix,
+        .global_opts = ao->global_opts,
+        .hidden = ao->encode,
+        .p = ao,
+    };
+    return true;
+}
+
+// For the ao option
+static const struct m_obj_list ao_obj_list = {
+    .get_desc = get_desc,
+    .description = "audio outputs",
+    .allow_trailer = true,
+    .disallow_positional_parameters = true,
+    .use_global_options = true,
+};
+
+#define OPT_BASE_STRUCT struct ao_opts
+const struct m_sub_options ao_conf = {
+    .opts = (const struct m_option[]) {
+        {"ao", OPT_SETTINGSLIST(audio_driver_list, &ao_obj_list),
+            .flags = UPDATE_AUDIO},
+        {"audio-device", OPT_STRING(audio_device), .flags = UPDATE_AUDIO},
+        {"audio-client-name", OPT_STRING(audio_client_name), .flags = UPDATE_AUDIO},
+        {"audio-buffer", OPT_DOUBLE(audio_buffer),
+            .flags = UPDATE_AUDIO, M_RANGE(0, 10)},
+        {0}
+    },
+    .size = sizeof(OPT_BASE_STRUCT),
+    .defaults = &(const OPT_BASE_STRUCT){
+        .audio_buffer = 0.2,
+        .audio_device = "auto",
+        .audio_client_name = "mpv",
+    },
+};
+
+static struct ao *ao_alloc(bool probing, struct mpv_global *global,
+                           void (*wakeup_cb)(void *ctx), void *wakeup_ctx,
+                           char *name)
+{
+    assert(wakeup_cb);
+
+    struct mp_log *log = mp_log_new(NULL, global->log, "ao");
+    struct m_obj_desc desc;
+    if (!m_obj_list_find(&desc, &ao_obj_list, bstr0(name))) {
+        mp_msg(log, MSGL_ERR, "Audio output %s not found!\n", name);
+        talloc_free(log);
+        return NULL;
+    };
+    struct ao_opts *opts = mp_get_config_group(NULL, global, &ao_conf);
+    struct ao *ao = talloc_ptrtype(NULL, ao);
+    talloc_steal(ao, log);
+    *ao = (struct ao) {
+        .driver = desc.p,
+        .probing = probing,
+        .global = global,
+        .wakeup_cb = wakeup_cb,
+        .wakeup_ctx = wakeup_ctx,
+        .log = mp_log_new(ao, log, name),
+        .def_buffer = opts->audio_buffer,
+        .client_name = talloc_strdup(ao, opts->audio_client_name),
+    };
+    talloc_free(opts);
+    ao->priv = m_config_group_from_desc(ao, ao->log, global, &desc, name);
+    if (!ao->priv)
+        goto error;
+    ao_set_gain(ao, 1.0f);
+    return ao;
+error:
+    talloc_free(ao);
+    return NULL;
+}
+
+static struct ao *ao_init(bool probing, struct mpv_global *global,
+                          void (*wakeup_cb)(void *ctx), void *wakeup_ctx,
+                          struct encode_lavc_context *encode_lavc_ctx, int flags,
+                          int samplerate, int format, struct mp_chmap channels,
+                          char *dev, char *name)
+{
+    struct ao *ao = ao_alloc(probing, global, wakeup_cb, wakeup_ctx, name);
+    if (!ao)
+        return NULL;
+    ao->samplerate = samplerate;
+    ao->channels = channels;
+    ao->format = format;
+    ao->encode_lavc_ctx = encode_lavc_ctx;
+    ao->init_flags = flags;
+    if (ao->driver->encode != !!ao->encode_lavc_ctx)
+        goto fail;
+
+    MP_VERBOSE(ao, "requested format: %d Hz, %s channels, %s\n",
+               ao->samplerate, mp_chmap_to_str(&ao->channels),
+               af_fmt_to_str(ao->format));
+
+    ao->device = talloc_strdup(ao, dev);
+    ao->stream_silence = flags & AO_INIT_STREAM_SILENCE;
+
+    init_buffer_pre(ao);
+
+    int r = ao->driver->init(ao);
+    if (r < 0) {
+        // Silly exception for coreaudio spdif redirection
+        if (ao->redirect) {
+            char redirect[80], rdevice[80];
+            snprintf(redirect, sizeof(redirect), "%s", ao->redirect);
+            snprintf(rdevice, sizeof(rdevice), "%s", ao->device ? ao->device : "");
+            ao_uninit(ao);
+            return ao_init(probing, global, wakeup_cb, wakeup_ctx,
+                           encode_lavc_ctx, flags, samplerate, format, channels,
+                           rdevice, redirect);
+        }
+        goto fail;
+    }
+    ao->driver_initialized = true;
+
+    ao->sstride = af_fmt_to_bytes(ao->format);
+    ao->num_planes = 1;
+    if (af_fmt_is_planar(ao->format)) {
+        ao->num_planes = ao->channels.num;
+    } else {
+        ao->sstride *= ao->channels.num;
+    }
+    ao->bps = ao->samplerate * ao->sstride;
+
+    if (ao->device_buffer <= 0 && ao->driver->write) {
+        MP_ERR(ao, "Device buffer size not set.\n");
+        goto fail;
+    }
+    if (ao->device_buffer)
+        MP_VERBOSE(ao, "device buffer: %d samples.\n", ao->device_buffer);
+    ao->buffer = MPMAX(ao->device_buffer, ao->def_buffer * ao->samplerate);
+    ao->buffer = MPMAX(ao->buffer, 1);
+
+    int align = af_format_sample_alignment(ao->format);
+    ao->buffer = (ao->buffer + align - 1) / align * align;
+    MP_VERBOSE(ao, "using soft-buffer of %d samples.\n", ao->buffer);
+
+    if (!init_buffer_post(ao))
+        goto fail;
+    return ao;
+
+fail:
+    ao_uninit(ao);
+    return NULL;
+}
+
+static void split_ao_device(void *tmp, char *opt, char **out_ao, char **out_dev)
+{
+    *out_ao = NULL;
+    *out_dev = NULL;
+    if (!opt)
+        return;
+    if (!opt[0] || strcmp(opt, "auto") == 0)
+        return;
+    // Split on "/". If "/" is the final character, or absent, out_dev is NULL.
+    bstr b_dev, b_ao;
+    bstr_split_tok(bstr0(opt), "/", &b_ao, &b_dev);
+    if (b_dev.len > 0)
+        *out_dev = bstrto0(tmp, b_dev);
+    *out_ao = bstrto0(tmp, b_ao);
+}
+
+struct ao *ao_init_best(struct mpv_global *global,
+                        int init_flags,
+                        void (*wakeup_cb)(void *ctx), void *wakeup_ctx,
+                        struct encode_lavc_context *encode_lavc_ctx,
+                        int samplerate, int format, struct mp_chmap channels)
+{
+    void *tmp = talloc_new(NULL);
+    struct ao_opts *opts = mp_get_config_group(tmp, global, &ao_conf);
+    struct mp_log *log = mp_log_new(tmp, global->log, "ao");
+    struct ao *ao = NULL;
+    struct m_obj_settings *ao_list = NULL;
+    int ao_num = 0;
+
+    for (int n = 0; opts->audio_driver_list && opts->audio_driver_list[n].name; n++)
+        MP_TARRAY_APPEND(tmp, ao_list, ao_num, opts->audio_driver_list[n]);
+
+    bool forced_dev = false;
+    char *pref_ao, *pref_dev;
+    split_ao_device(tmp, opts->audio_device, &pref_ao, &pref_dev);
+    if (!ao_num && pref_ao) {
+        // Reuse the autoselection code
+        MP_TARRAY_APPEND(tmp, ao_list, ao_num,
+            (struct m_obj_settings){.name = pref_ao});
+        forced_dev = true;
+    }
+
+    bool autoprobe = ao_num == 0;
+
+    // Something like "--ao=a,b," means do autoprobing after a and b fail.
+    if (ao_num && strlen(ao_list[ao_num - 1].name) == 0) {
+        ao_num -= 1;
+        autoprobe = true;
+    }
+
+    if (autoprobe) {
+        for (int n = 0; n < MP_ARRAY_SIZE(audio_out_drivers); n++) {
+            const struct ao_driver *driver = audio_out_drivers[n];
+            if (driver == &audio_out_null)
+                break;
+            MP_TARRAY_APPEND(tmp, ao_list, ao_num,
+                (struct m_obj_settings){.name = (char *)driver->name});
+        }
+    }
+
+    if (init_flags & AO_INIT_NULL_FALLBACK) {
+        MP_TARRAY_APPEND(tmp, ao_list, ao_num,
+            (struct m_obj_settings){.name = "null"});
+    }
+
+    for (int n = 0; n < ao_num; n++) {
+        struct m_obj_settings *entry = &ao_list[n];
+        bool probing = n + 1 != ao_num;
+        mp_verbose(log, "Trying audio driver '%s'\n", entry->name);
+        char *dev = NULL;
+        if (pref_ao && pref_dev && strcmp(entry->name, pref_ao) == 0) {
+            dev = pref_dev;
+            mp_verbose(log, "Using preferred device '%s'\n", dev);
+        }
+        ao = ao_init(probing, global, wakeup_cb, wakeup_ctx, encode_lavc_ctx,
+                     init_flags, samplerate, format, channels, dev, entry->name);
+        if (ao)
+            break;
+        if (!probing)
+            mp_err(log, "Failed to initialize audio driver '%s'\n", entry->name);
+        if (dev && forced_dev) {
+            mp_err(log, "This audio driver/device was forced with the "
+                        "--audio-device option.\nTry unsetting it.\n");
+        }
+    }
+
+    talloc_free(tmp);
+    return ao;
+}
+
+// Query the AO_EVENT_*s as requested by the events parameter, and return them.
+int ao_query_and_reset_events(struct ao *ao, int events)
+{
+    return atomic_fetch_and(&ao->events_, ~(unsigned)events) & events;
+}
+
+// Returns events that were set by this calls.
+int ao_add_events(struct ao *ao, int events)
+{
+    unsigned prev_events = atomic_fetch_or(&ao->events_, events);
+    unsigned new = events & ~prev_events;
+    if (new)
+        ao->wakeup_cb(ao->wakeup_ctx);
+    return new;
+}
+
+// Request that the player core destroys and recreates the AO. Fully thread-safe.
+void ao_request_reload(struct ao *ao)
+{
+    ao_add_events(ao, AO_EVENT_RELOAD);
+}
+
+// Notify the player that the device list changed. Fully thread-safe.
+void ao_hotplug_event(struct ao *ao)
+{
+    ao_add_events(ao, AO_EVENT_HOTPLUG);
+}
+
+bool ao_chmap_sel_adjust(struct ao *ao, const struct mp_chmap_sel *s,
+                         struct mp_chmap *map)
+{
+    MP_VERBOSE(ao, "Channel layouts:\n");
+    mp_chmal_sel_log(s, ao->log, MSGL_V);
+    bool r = mp_chmap_sel_adjust(s, map);
+    if (r)
+        MP_VERBOSE(ao, "result: %s\n", mp_chmap_to_str(map));
+    return r;
+}
+
+// safe_multichannel=true behaves like ao_chmap_sel_adjust.
+// safe_multichannel=false is a helper for callers which do not support safe
+// handling of arbitrary channel layouts. If the multichannel layouts are not
+// considered "always safe" (e.g. HDMI), then allow only stereo or mono, if
+// they are part of the list in *s.
+bool ao_chmap_sel_adjust2(struct ao *ao, const struct mp_chmap_sel *s,
+                          struct mp_chmap *map, bool safe_multichannel)
+{
+    if (!safe_multichannel && (ao->init_flags & AO_INIT_SAFE_MULTICHANNEL_ONLY)) {
+        struct mp_chmap res = *map;
+        if (mp_chmap_sel_adjust(s, &res)) {
+            if (!mp_chmap_equals(&res, &(struct mp_chmap)MP_CHMAP_INIT_MONO) &&
+                !mp_chmap_equals(&res, &(struct mp_chmap)MP_CHMAP_INIT_STEREO))
+            {
+                MP_VERBOSE(ao, "Disabling multichannel output.\n");
+                *map = (struct mp_chmap)MP_CHMAP_INIT_STEREO;
+            }
+        }
+    }
+
+    return ao_chmap_sel_adjust(ao, s, map);
+}
+
+bool ao_chmap_sel_get_def(struct ao *ao, const struct mp_chmap_sel *s,
+                          struct mp_chmap *map, int num)
+{
+    return mp_chmap_sel_get_def(s, map, num);
+}
+
+// --- The following functions just return immutable information.
+
+void ao_get_format(struct ao *ao,
+                   int *samplerate, int *format, struct mp_chmap *channels)
+{
+    *samplerate = ao->samplerate;
+    *format = ao->format;
+    *channels = ao->channels;
+}
+
+const char *ao_get_name(struct ao *ao)
+{
+    return ao->driver->name;
+}
+
+const char *ao_get_description(struct ao *ao)
+{
+    return ao->driver->description;
+}
+
+bool ao_untimed(struct ao *ao)
+{
+    return ao->untimed;
+}
+
+// ---
+
+struct ao_hotplug {
+    struct mpv_global *global;
+    void (*wakeup_cb)(void *ctx);
+    void *wakeup_ctx;
+    // A single AO instance is used to listen to hotplug events. It wouldn't
+    // make much sense to allow multiple AO drivers; all sane platforms have
+    // a single audio API providing all events.
+    // This is _not_ necessarily the same AO instance as used for playing
+    // audio.
+    struct ao *ao;
+    // cached
+    struct ao_device_list *list;
+    bool needs_update;
+};
+
+struct ao_hotplug *ao_hotplug_create(struct mpv_global *global,
+                                     void (*wakeup_cb)(void *ctx),
+                                     void *wakeup_ctx)
+{
+    struct ao_hotplug *hp = talloc_ptrtype(NULL, hp);
+    *hp = (struct ao_hotplug){
+        .global = global,
+        .wakeup_cb = wakeup_cb,
+        .wakeup_ctx = wakeup_ctx,
+        .needs_update = true,
+    };
+    return hp;
+}
+
+static void get_devices(struct ao *ao, struct ao_device_list *list)
+{
+    if (ao->driver->list_devs) {
+        ao->driver->list_devs(ao, list);
+    } else {
+        ao_device_list_add(list, ao, &(struct ao_device_desc){"", ""});
+    }
+}
+
+bool ao_hotplug_check_update(struct ao_hotplug *hp)
+{
+    if (hp->ao && ao_query_and_reset_events(hp->ao, AO_EVENT_HOTPLUG)) {
+        hp->needs_update = true;
+        return true;
+    }
+    return false;
+}
+
+// The return value is valid until the next call to this API.
+struct ao_device_list *ao_hotplug_get_device_list(struct ao_hotplug *hp,
+                                                  struct ao *playback_ao)
+{
+    if (hp->list && !hp->needs_update)
+        return hp->list;
+
+    talloc_free(hp->list);
+    struct ao_device_list *list = talloc_zero(hp, struct ao_device_list);
+    hp->list = list;
+
+    MP_TARRAY_APPEND(list, list->devices, list->num_devices,
+        (struct ao_device_desc){"auto", "Autoselect device"});
+
+    // Try to use the same AO for hotplug handling as for playback.
+    // Different AOs may not agree and the playback one is the only one the
+    // user knows about and may even have configured explicitly.
+    if (!hp->ao && playback_ao && playback_ao->driver->hotplug_init) {
+        struct ao *ao = ao_alloc(true, hp->global, hp->wakeup_cb, hp->wakeup_ctx,
+                                 (char *)playback_ao->driver->name);
+        if (playback_ao->driver->hotplug_init(ao) >= 0) {
+            hp->ao = ao;
+        } else {
+            talloc_free(ao);
+        }
+    }
+
+    for (int n = 0; n < MP_ARRAY_SIZE(audio_out_drivers); n++) {
+        const struct ao_driver *d = audio_out_drivers[n];
+        if (d == &audio_out_null)
+            break; // don't add unsafe/special entries
+
+        struct ao *ao = ao_alloc(true, hp->global, hp->wakeup_cb, hp->wakeup_ctx,
+                                 (char *)d->name);
+        if (!ao)
+            continue;
+
+        if (ao->driver->hotplug_init) {
+            if (ao->driver->hotplug_init(ao) >= 0) {
+                get_devices(ao, list);
+                if (hp->ao)
+                    ao->driver->hotplug_uninit(ao);
+                else
+                    hp->ao = ao; // keep this one
+            }
+        } else {
+            get_devices(ao, list);
+        }
+        if (ao != hp->ao)
+            talloc_free(ao);
+    }
+    hp->needs_update = false;
+    return list;
+}
+
+void ao_device_list_add(struct ao_device_list *list, struct ao *ao,
+                        struct ao_device_desc *e)
+{
+    struct ao_device_desc c = *e;
+    const char *dname = ao->driver->name;
+    char buf[80];
+    if (!c.desc || !c.desc[0]) {
+        if (c.name && c.name[0]) {
+            c.desc = c.name;
+        } else if (list->num_devices) {
+            // Assume this is the default device.
+            snprintf(buf, sizeof(buf), "Default (%s)", dname);
+            c.desc = buf;
+        } else {
+            // First default device (and maybe the only one).
+            c.desc = "Default";
+        }
+    }
+    c.name = (c.name && c.name[0]) ? talloc_asprintf(list, "%s/%s", dname, c.name)
+                                   : talloc_strdup(list, dname);
+    c.desc = talloc_strdup(list, c.desc);
+    MP_TARRAY_APPEND(list, list->devices, list->num_devices, c);
+}
+
+void ao_hotplug_destroy(struct ao_hotplug *hp)
+{
+    if (!hp)
+        return;
+    if (hp->ao && hp->ao->driver->hotplug_uninit)
+        hp->ao->driver->hotplug_uninit(hp->ao);
+    talloc_free(hp->ao);
+    talloc_free(hp);
+}
+
+static void dummy_wakeup(void *ctx)
+{
+}
+
+void ao_print_devices(struct mpv_global *global, struct mp_log *log,
+                      struct ao *playback_ao)
+{
+    struct ao_hotplug *hp = ao_hotplug_create(global, dummy_wakeup, NULL);
+    struct ao_device_list *list = ao_hotplug_get_device_list(hp, playback_ao);
+    mp_info(log, "List of detected audio devices:\n");
+    for (int n = 0; n < list->num_devices; n++) {
+        struct ao_device_desc *desc = &list->devices[n];
+        mp_info(log, "  '%s' (%s)\n", desc->name, desc->desc);
+    }
+    ao_hotplug_destroy(hp);
+}
+
+void ao_set_gain(struct ao *ao, float gain)
+{
+    atomic_store(&ao->gain, gain);
+}
+
+#define MUL_GAIN_i(d, num_samples, gain, low, center, high)                     \
+    for (int n = 0; n < (num_samples); n++)                                     \
+        (d)[n] = MPCLAMP(                                                       \
+            ((((int64_t)((d)[n]) - (center)) * (gain) + 128) >> 8) + (center),  \
+            (low), (high))
+
+#define MUL_GAIN_f(d, num_samples, gain)                                        \
+    for (int n = 0; n < (num_samples); n++)                                     \
+        (d)[n] = MPCLAMP(((d)[n]) * (gain), -1.0, 1.0)
+
+static void process_plane(struct ao *ao, void *data, int num_samples)
+{
+    float gain = atomic_load_explicit(&ao->gain, memory_order_relaxed);
+    int gi = lrint(256.0 * gain);
+    if (gi == 256)
+        return;
+    switch (af_fmt_from_planar(ao->format)) {
+    case AF_FORMAT_U8:
+        MUL_GAIN_i((uint8_t *)data, num_samples, gi, 0, 128, 255);
+        break;
+    case AF_FORMAT_S16:
+        MUL_GAIN_i((int16_t *)data, num_samples, gi, INT16_MIN, 0, INT16_MAX);
+        break;
+    case AF_FORMAT_S32:
+        MUL_GAIN_i((int32_t *)data, num_samples, gi, INT32_MIN, 0, INT32_MAX);
+        break;
+    case AF_FORMAT_FLOAT:
+        MUL_GAIN_f((float *)data, num_samples, gain);
+        break;
+    case AF_FORMAT_DOUBLE:
+        MUL_GAIN_f((double *)data, num_samples, gain);
+        break;
+    default:;
+        // all other sample formats are simply not supported
+    }
+}
+
+void ao_post_process_data(struct ao *ao, void **data, int num_samples)
+{
+    bool planar = af_fmt_is_planar(ao->format);
+    int planes = planar ? ao->channels.num : 1;
+    int plane_samples = num_samples * (planar ? 1: ao->channels.num);
+    for (int n = 0; n < planes; n++)
+        process_plane(ao, data[n], plane_samples);
+}
+
+static int get_conv_type(struct ao_convert_fmt *fmt)
+{
+    if (af_fmt_to_bytes(fmt->src_fmt) * 8 == fmt->dst_bits && !fmt->pad_msb)
+        return 0; // passthrough
+    if (fmt->src_fmt == AF_FORMAT_S32 && fmt->dst_bits == 24 && !fmt->pad_msb)
+        return 1; // simple 32->24 bit conversion
+    if (fmt->src_fmt == AF_FORMAT_S32 && fmt->dst_bits == 32 && fmt->pad_msb == 8)
+        return 2; // simple 32->24 bit conversion, with MSB padding
+    return -1; // unsupported
+}
+
+// Check whether ao_convert_inplace() can be called. As an exception, the
+// planar-ness of the sample format and the number of channels is ignored.
+// All other parameters must be as passed to ao_convert_inplace().
+bool ao_can_convert_inplace(struct ao_convert_fmt *fmt)
+{
+    return get_conv_type(fmt) >= 0;
+}
+
+bool ao_need_conversion(struct ao_convert_fmt *fmt)
+{
+    return get_conv_type(fmt) != 0;
+}
+
+// The LSB is always ignored.
+#if BYTE_ORDER == BIG_ENDIAN
+#define SHIFT24(x) ((3-(x))*8)
+#else
+#define SHIFT24(x) (((x)+1)*8)
+#endif
+
+static void convert_plane(int type, void *data, int num_samples)
+{
+    switch (type) {
+    case 0:
+        break;
+    case 1: /* fall through */
+    case 2: {
+        int bytes = type == 1 ? 3 : 4;
+        for (int s = 0; s < num_samples; s++) {
+            uint32_t val = *((uint32_t *)data + s);
+            uint8_t *ptr = (uint8_t *)data + s * bytes;
+            ptr[0] = val >> SHIFT24(0);
+            ptr[1] = val >> SHIFT24(1);
+            ptr[2] = val >> SHIFT24(2);
+            if (type == 2)
+                ptr[3] = 0;
+        }
+        break;
+    }
+    default:
+        MP_ASSERT_UNREACHABLE();
+    }
+}
+
+// data[n] contains the pointer to the first sample of the n-th plane, in the
+// format implied by fmt->src_fmt. src_fmt also controls whether the data is
+// all in one plane, or if there is a plane per channel.
+void ao_convert_inplace(struct ao_convert_fmt *fmt, void **data, int num_samples)
+{
+    int type = get_conv_type(fmt);
+    bool planar = af_fmt_is_planar(fmt->src_fmt);
+    int planes = planar ? fmt->channels : 1;
+    int plane_samples = num_samples * (planar ? 1: fmt->channels);
+    for (int n = 0; n < planes; n++)
+        convert_plane(type, data[n], plane_samples);
+}