ao_portaudio: add new PortAudio audio output driver

This AO has potential to be useful on platforms other than Linux. On
Windows in particular, PortAudio can make use of newer/better audio
APIs like WASAPI, instead of DirectSound.

As an implementation choice, the PortAudio callback API was used. The
blocking API might be a better match for mplayer's requirements, but
caused severe problems on Linux/ALSA (possibly PortAudio bugs).

Makefile

@@ -468,6 +468,7 @@ SRCS_MPLAYER-$(OPENAL)        += libao2/ao_openal.c
 SRCS_MPLAYER-$(OSS)           += libao2/ao_oss.c
 SRCS_MPLAYER-$(PNM)           += libvo/vo_pnm.c
 SRCS_MPLAYER-$(PULSE)         += libao2/ao_pulse.c
+SRCS_MPLAYER-$(PORTAUDIO)     += libao2/ao_portaudio.c
 SRCS_MPLAYER-$(RSOUND)        += libao2/ao_rsound.c
 SRCS_MPLAYER-$(S3FB)          += libvo/vo_s3fb.c
 SRCS_MPLAYER-$(SDL)           += libao2/ao_sdl.c libvo/vo_sdl.c libvo/sdl_common.c

configure

@@ -443,6 +443,7 @@ Audio output:
   --disable-esd          disable esd audio output [autodetect]
   --disable-rsound       disable RSound audio output [autodetect]
   --disable-pulse        disable Pulseaudio audio output [autodetect]
+  --disable-portaudio    disable PortAudio audio output [autodetect]
   --disable-jack         disable JACK audio output [autodetect]
   --enable-openal        enable OpenAL audio output [disable]
   --disable-nas          disable NAS audio output [autodetect]
@@ -602,6 +603,7 @@ _arts=auto
 _esd=auto
 _rsound=auto
 _pulse=auto
+_portaudio=auto
 _jack=auto
 _openal=no
 _libcdio=auto
@@ -924,6 +926,8 @@ for ac_option do
   --disable-rsound)     _rsound=no      ;;
   --enable-pulse)       _pulse=yes      ;;
   --disable-pulse)      _pulse=no       ;;
+  --enable-portaudio)   _portaudio=yes  ;;
+  --disable-portaudio)  _portaudio=no   ;;
   --enable-jack)        _jack=yes       ;;
   --disable-jack)       _jack=no        ;;
   --enable-openal)      _openal=yes     ;;
@@ -4898,6 +4902,28 @@ else
 fi
 
 
+echocheck "PortAudio"
+if test "$_portaudio" = auto && test "$_pthreads" != yes ; then
+    _portaudio=no
+    res_comment="pthreads not enabled"
+fi
+if test "$_portaudio" = auto ; then
+  _portaudio=no
+  if pkg_config_add 'portaudio-2.0 >= 19' ; then
+      _portaudio=yes
+  fi
+fi
+echores "$_portaudio"
+
+if test "$_portaudio" = yes ; then
+  def_portaudio='#define CONFIG_PORTAUDIO 1'
+  aomodules="portaudio $aomodules"
+else
+  def_portaudio='#undef CONFIG_PORTAUDIO'
+  noaomodules="portaudio $noaomodules"
+fi
+
+
 echocheck "JACK"
 if test "$_jack" = auto ; then
   _jack=no
@@ -6433,6 +6459,7 @@ PNG = $_png
 PNM = $_pnm
 PRIORITY = $_priority
 PULSE = $_pulse
+PORTAUDIO = $_portaudio
 PVR = $_pvr
 QTX_CODECS = $_qtx
 QTX_CODECS_WIN32 = $_qtx_codecs_win32
@@ -6710,6 +6737,7 @@ $def_ossaudio
 $def_ossaudio_devdsp
 $def_ossaudio_devmixer
 $def_pulse
+$def_portaudio
 $def_rsound
 $def_sgiaudio
 $def_sunaudio

libao2/ao_portaudio.c

@@ -0,0 +1,431 @@
+/*
+ * This file is part of mplayer2.
+ *
+ * mplayer2 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.
+ *
+ * mplayer2 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 mplayer2.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <pthread.h>
+
+#include <libavutil/avutil.h>
+#include <portaudio.h>
+
+#include "config.h"
+#include "subopt-helper.h"
+#include "libaf/af_format.h"
+#include "mp_msg.h"
+#include "audio_out.h"
+
+struct priv {
+    PaStream *stream;
+    int framelen;
+
+    pthread_mutex_t ring_mutex;
+
+    // protected by ring_mutex
+    unsigned char *ring;
+    int ring_size;      // max size of the ring
+    int read_pos;       // points to first byte that can be read
+    int read_len;       // number of bytes that can be read
+    double play_time;   // time when last packet returned to PA is on speaker
+                        // 0 is N/A (0 is not a valid PA time value)
+    int play_silence;   // play this many bytes of silence, before real data
+    bool play_remaining;// play what's left in the buffer, then stop stream
+};
+
+struct format_map {
+    int mp_format;
+    PaSampleFormat pa_format;
+};
+
+static const struct format_map format_maps[] = {
+    // first entry is the default format
+    {AF_FORMAT_S16_NE,      paInt16},
+    {AF_FORMAT_S24_NE,      paInt24},
+    {AF_FORMAT_S32_NE,      paInt32},
+    {AF_FORMAT_S8,          paInt8},
+    {AF_FORMAT_U8,          paUInt8},
+    {AF_FORMAT_FLOAT_NE,    paFloat32},
+    {AF_FORMAT_UNKNOWN,     0}
+};
+
+static void print_help(void)
+{
+    mp_msg(MSGT_AO, MSGL_FATAL,
+           "\n-ao portaudio commandline help:\n"
+          "Example: mplayer -ao portaudio:device=subdevice\n"
+          "\nOptions:\n"
+          "   device=subdevice\n"
+          "      Audio device PortAudio should use. Devices can be listed\n"
+          "      with -ao portaudio:device=help\n"
+          "      The subdevice can be passed as index, or as complete name.\n");
+}
+
+static bool check_pa_ret(int ret)
+{
+    if (ret < 0) {
+        mp_msg(MSGT_AO, MSGL_ERR, "[portaudio] %s\n",
+               Pa_GetErrorText(ret));
+        if (ret == paUnanticipatedHostError) {
+            const PaHostErrorInfo* hosterr = Pa_GetLastHostErrorInfo();
+            mp_msg(MSGT_AO, MSGL_ERR, "[portaudio] Host error: %s\n",
+                   hosterr->errorText);
+        }
+        return false;
+    }
+    return true;
+}
+
+// Amount of bytes that contain audio of the given duration, aligned to frames.
+static int seconds_to_bytes(struct ao *ao, double duration_seconds)
+{
+    struct priv *priv = ao->priv;
+
+    int bytes = duration_seconds * ao->bps;
+    if (bytes % priv->framelen)
+        bytes += priv->framelen - (bytes % priv->framelen);
+    return bytes;
+}
+
+static int to_int(const char *s, int return_on_error)
+{
+    char *endptr;
+    int res = strtol(s, &endptr, 10);
+    return (s[0] && !endptr[0]) ? res : return_on_error;
+}
+
+static int find_device(struct ao *ao, const char *name)
+{
+    int help = strcmp(name, "help") == 0;
+    int count = Pa_GetDeviceCount();
+    check_pa_ret(count);
+    int found = paNoDevice;
+    int index = to_int(name, -1);
+    if (help)
+        mp_msg(MSGT_AO, MSGL_INFO, "PortAudio devices:\n");
+    for (int n = 0; n < count; n++) {
+        const PaDeviceInfo* info = Pa_GetDeviceInfo(n);
+        if (help) {
+            if (info->maxOutputChannels < 1)
+                continue;
+            mp_msg(MSGT_AO, MSGL_INFO, "  %d '%s', %d channels, latency: %.2f "
+                   "ms, sample rate: %.0f\n", n, info->name,
+                   info->maxOutputChannels,
+                   info->defaultHighOutputLatency * 1000,
+                   info->defaultSampleRate);
+        }
+        if (strcmp(name, info->name) == 0 || n == index) {
+            found = n;
+            break;
+        }
+    }
+    if (found == paNoDevice && !help)
+        mp_msg(MSGT_AO, MSGL_FATAL, "[portaudio] Device '%s' not found!\n",
+               name);
+    return found;
+}
+
+static int ring_write(struct ao *ao, unsigned char *data, int len)
+{
+    struct priv *priv = ao->priv;
+
+    int free = priv->ring_size - priv->read_len;
+    int write_pos = (priv->read_pos + priv->read_len) % priv->ring_size;
+    int write_len = FFMIN(len, free);
+    int len1 = FFMIN(priv->ring_size - write_pos, write_len);
+    int len2 = write_len - len1;
+
+    memcpy(priv->ring + write_pos, data, len1);
+    memcpy(priv->ring, data + len1, len2);
+
+    priv->read_len += write_len;
+
+    return write_len;
+}
+
+static int ring_read(struct ao *ao, unsigned char *data, int len)
+{
+    struct priv *priv = ao->priv;
+
+    int read_len = FFMIN(len, priv->read_len);
+    int len1 = FFMIN(priv->ring_size - priv->read_pos, read_len);
+    int len2 = read_len - len1;
+
+    memcpy(data, priv->ring + priv->read_pos, len1);
+    memcpy(data + len1, priv->ring, len2);
+
+    priv->read_len -= read_len;
+    priv->read_pos = (priv->read_pos + read_len) % priv->ring_size;
+
+    return read_len;
+}
+
+static void fill_silence(unsigned char *ptr, int len)
+{
+    memset(ptr, 0, len);
+}
+
+static int stream_callback(const void *input,
+                           void *output_v,
+                           unsigned long frameCount,
+                           const PaStreamCallbackTimeInfo *timeInfo,
+                           PaStreamCallbackFlags statusFlags,
+                           void *userData)
+{
+    struct ao *ao = userData;
+    struct priv *priv = ao->priv;
+    int res = paContinue;
+    unsigned char *output = output_v;
+    int len_bytes = frameCount * priv->framelen;
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    // NOTE: PA + ALSA in dmix mode seems to pretend that there is no latency
+    //       (outputBufferDacTime == currentTime)
+    priv->play_time = timeInfo->outputBufferDacTime
+                      + len_bytes / (float)ao->bps;
+
+    if (priv->play_silence > 0) {
+        int bytes = FFMIN(priv->play_silence, len_bytes);
+        fill_silence(output, bytes);
+        priv->play_silence -= bytes;
+        len_bytes -= bytes;
+        output += bytes;
+    }
+    int read = ring_read(ao, output, len_bytes);
+    len_bytes -= read;
+    output += read;
+
+    if (len_bytes > 0) {
+        if (priv->play_remaining) {
+            res = paComplete;
+            priv->play_remaining = false;
+        } else {
+            mp_msg(MSGT_AO, MSGL_ERR, "[portaudio] Buffer underflow!\n");
+        }
+        fill_silence(output, len_bytes);
+    }
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+
+    return res;
+}
+
+static void uninit(struct ao *ao, bool cut_audio)
+{
+    struct priv *priv = ao->priv;
+
+    if (priv->stream) {
+        if (!cut_audio && Pa_IsStreamActive(priv->stream) == 1) {
+            pthread_mutex_lock(&priv->ring_mutex);
+
+            priv->play_remaining = true;
+
+            pthread_mutex_unlock(&priv->ring_mutex);
+
+            check_pa_ret(Pa_StopStream(priv->stream));
+        }
+        check_pa_ret(Pa_CloseStream(priv->stream));
+    }
+
+    pthread_mutex_destroy(&priv->ring_mutex);
+    Pa_Terminate();
+}
+
+static int init(struct ao *ao, char *params)
+{
+    struct priv *priv = talloc_zero(ao, struct priv);
+    ao->priv = priv;
+
+    if (!check_pa_ret(Pa_Initialize()))
+        return -1;
+
+    pthread_mutex_init(&priv->ring_mutex, NULL);
+
+    char *device = NULL;
+    const opt_t subopts[] = {
+        {"device", OPT_ARG_MSTRZ, &device, NULL},
+        {NULL}
+    };
+    if (subopt_parse(params, subopts) != 0) {
+        print_help();
+        goto error_exit;
+    }
+
+    int pa_device = Pa_GetDefaultOutputDevice();
+    if (device)
+        pa_device = find_device(ao, device);
+    if (pa_device == paNoDevice)
+        goto error_exit;
+
+    PaStreamParameters sp = {
+        .device = pa_device,
+        .channelCount = ao->channels,
+        .suggestedLatency
+            = Pa_GetDeviceInfo(pa_device)->defaultHighOutputLatency,
+    };
+
+    const struct format_map *fmt = format_maps;
+    while (fmt->pa_format) {
+        if (fmt->mp_format == ao->format) {
+            PaStreamParameters test = sp;
+            test.sampleFormat = fmt->pa_format;
+            if (Pa_IsFormatSupported(NULL, &test, ao->samplerate) == paNoError)
+                break;
+        }
+        fmt++;
+    }
+    if (!fmt->pa_format) {
+        mp_msg(MSGT_AO, MSGL_V,
+               "[portaudio] Unsupported format, using default.\n");
+        fmt = format_maps;
+    }
+
+    ao->format = fmt->mp_format;
+    sp.sampleFormat = fmt->pa_format;
+    priv->framelen = ao->channels * (af_fmt2bits(ao->format) / 8);
+    ao->bps = ao->samplerate * priv->framelen;
+
+    if (!check_pa_ret(Pa_IsFormatSupported(NULL, &sp, ao->samplerate)))
+        goto error_exit;
+    if (!check_pa_ret(Pa_OpenStream(&priv->stream, NULL, &sp, ao->samplerate,
+                                    paFramesPerBufferUnspecified, paNoFlag,
+                                    stream_callback, ao)))
+        goto error_exit;
+
+    priv->ring_size = seconds_to_bytes(ao, 0.5);
+    priv->ring = talloc_zero_size(priv, priv->ring_size);
+
+    free(device);
+    return 0;
+
+error_exit:
+    uninit(ao, true);
+    free(device);
+    return -1;
+}
+
+static int play(struct ao *ao, void *data, int len, int flags)
+{
+    struct priv *priv = ao->priv;
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    int write_len = ring_write(ao, data, len);
+    if (flags & AOPLAY_FINAL_CHUNK)
+        priv->play_remaining = true;
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+
+    if (Pa_IsStreamStopped(priv->stream) == 1)
+        check_pa_ret(Pa_StartStream(priv->stream));
+
+    return write_len;
+}
+
+static int get_space(struct ao *ao)
+{
+    struct priv *priv = ao->priv;
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    int free = priv->ring_size - priv->read_len;
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+
+    return free;
+}
+
+static float get_delay(struct ao *ao)
+{
+    struct priv *priv = ao->priv;
+
+    double stream_time = Pa_GetStreamTime(priv->stream);
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    float frame_time = priv->play_time ? priv->play_time - stream_time : 0;
+    float buffer_latency = (priv->read_len + priv->play_silence)
+                           / (float)ao->bps;
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+
+    return buffer_latency + frame_time;
+}
+
+static void reset(struct ao *ao)
+{
+    struct priv *priv = ao->priv;
+
+    if (Pa_IsStreamStopped(priv->stream) != 1)
+        check_pa_ret(Pa_AbortStream(priv->stream));
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    priv->read_len = 0;
+    priv->read_pos = 0;
+    priv->play_remaining = false;
+    priv->play_time = 0;
+    priv->play_silence = 0;
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+}
+
+static void pause(struct ao *ao)
+{
+    struct priv *priv = ao->priv;
+
+    check_pa_ret(Pa_AbortStream(priv->stream));
+
+    double stream_time = Pa_GetStreamTime(priv->stream);
+
+    pthread_mutex_lock(&priv->ring_mutex);
+
+    // When playback resumes, replace the lost audio (due to dropping the
+    // portaudio/driver/hardware internal buffers) with silence.
+    float frame_time = priv->play_time ? priv->play_time - stream_time : 0;
+    priv->play_silence += seconds_to_bytes(ao, FFMAX(frame_time, 0));
+    priv->play_time = 0;
+
+    pthread_mutex_unlock(&priv->ring_mutex);
+}
+
+static void resume(struct ao *ao)
+{
+    struct priv *priv = ao->priv;
+
+    check_pa_ret(Pa_StartStream(priv->stream));
+}
+
+const struct ao_driver audio_out_portaudio = {
+    .is_new = true,
+    .info = &(const struct ao_info) {
+        "PortAudio",
+        "portaudio",
+        "wm4",
+        "",
+    },
+    .init      = init,
+    .uninit    = uninit,
+    .reset     = reset,
+    .get_space = get_space,
+    .play      = play,
+    .get_delay = get_delay,
+    .pause     = pause,
+    .resume    = resume,
+};

libao2/audio_out.c

@@ -55,6 +55,7 @@ extern const struct ao_driver audio_out_v4l2;
 extern const struct ao_driver audio_out_mpegpes;
 extern const struct ao_driver audio_out_pcm;
 extern const struct ao_driver audio_out_pss;
+extern const struct ao_driver audio_out_portaudio;
 
 static const struct ao_driver * const audio_out_drivers[] = {
 // native:
@@ -82,6 +83,9 @@ static const struct ao_driver * const audio_out_drivers[] = {
 #ifdef CONFIG_OSS_AUDIO
     &audio_out_oss,
 #endif
+#ifdef CONFIG_PORTAUDIO
+    &audio_out_portaudio,
+#endif
 #ifdef CONFIG_SGI_AUDIO
     &audio_out_sgi,
 #endif