[FFmpeg-devel] [PATCH 5/6] lavd: add new API for iterating input and output devices

Josh de Kock josh at itanimul.li
Wed Jan 3 02:43:06 EET 2018


---
 configure                |  27 ++++++--
 libavdevice/alldevices.c | 172 +++++++++++++++++++++++++++++++++++------------
 libavdevice/avdevice.c   |  46 -------------
 libavdevice/avdevice.h   |  28 ++++++++
 libavdevice/version.h    |   4 ++
 5 files changed, 184 insertions(+), 93 deletions(-)

diff --git a/configure b/configure
index 7b46e5c..79eb95a 100755
--- a/configure
+++ b/configure
@@ -569,6 +569,12 @@ add_suffix(){
     for v; do echo ${v}${suffix}; done
 }
 
+remove_suffix(){
+    suffix=$1
+    shift
+    for v; do echo ${v%$suffix}; done
+}
+
 set_all(){
     value=$1
     shift
@@ -3525,17 +3531,18 @@ find_things(){
     sed -n "s/^[^#]*$pattern.*([^,]*, *\([^,]*\)\(,.*\)*).*/\1_$thing/p" "$file"
 }
 
-OUTDEV_LIST=$(find_things   outdev   OUTDEV   libavdevice/alldevices.c)
-INDEV_LIST=$(find_things    indev    _IN      libavdevice/alldevices.c)
 FILTER_LIST=$(find_things   filter   FILTER   libavfilter/allfilters.c)
 
 find_things_extern(){
     thing=$1
     pattern=$2
     file=$source_path/$3
-    sed -n "s/^[^#]*extern.*$pattern *ff_\([^ ]*\)_$thing;/\1_$thing/p" "$file"
+    out=${4:-$thing}
+    sed -n "s/^[^#]*extern.*$pattern *ff_\([^ ]*\)_$thing;/\1_$out/p" "$file"
 }
 
+OUTDEV_LIST=$(find_things_extern muxer AVOutputFormat libavdevice/alldevices.c outdev)
+INDEV_LIST=$(find_things_extern demuxer AVInputFormat libavdevice/alldevices.c indev)
 MUXER_LIST=$(find_things_extern muxer AVOutputFormat libavformat/allformats.c)
 DEMUXER_LIST=$(find_things_extern demuxer AVInputFormat libavformat/allformats.c)
 ENCODER_LIST=$(find_things_extern encoder AVCodec libavcodec/allcodecs.c)
@@ -7032,7 +7039,17 @@ print_enabled_components(){
     shift 3
     echo "static const $struct_name * const $name[] = {" > $TMPH
     for c in $*; do
-        enabled $c && printf "    &ff_%s,\n" $c >> $TMPH
+        if enabled $c; then
+            case $name in
+                indev_list)
+                    c=$(add_suffix _demuxer $(remove_suffix _indev $c))
+                ;;
+                outdev_list)
+                    c=$(add_suffix _muxer $(remove_suffix _outdev $c))
+                ;;
+            esac
+            printf "    &ff_%s,\n" $c >> $TMPH
+        fi
     done
     echo "    NULL };" >> $TMPH
     cp_if_changed $TMPH $file
@@ -7041,6 +7058,8 @@ print_enabled_components(){
 print_enabled_components libavcodec/codec_list.c AVCodec codec_list $CODEC_LIST
 print_enabled_components libavcodec/parser_list.c AVCodecParser parser_list $PARSER_LIST
 print_enabled_components libavcodec/bsf_list.c AVBitStreamFilter bitstream_filters $BSF_LIST
+print_enabled_components libavdevice/indev_list.c AVInputFormat indev_list $INDEV_LIST
+print_enabled_components libavdevice/outdev_list.c AVOutputFormat outdev_list $OUTDEV_LIST
 print_enabled_components libavformat/demuxer_list.c AVInputFormat demuxer_list $DEMUXER_LIST
 print_enabled_components libavformat/muxer_list.c AVOutputFormat muxer_list $MUXER_LIST
 print_enabled_components libavformat/protocol_list.c URLProtocol url_protocols $PROTOCOL_LIST
diff --git a/libavdevice/alldevices.c b/libavdevice/alldevices.c
index b767b6a..6b2a512 100644
--- a/libavdevice/alldevices.c
+++ b/libavdevice/alldevices.c
@@ -22,57 +22,143 @@
 #include "libavutil/thread.h"
 #include "avdevice.h"
 
-#define REGISTER_OUTDEV(X, x)                                           \
-    {                                                                   \
-        extern AVOutputFormat ff_##x##_muxer;                           \
-        if (CONFIG_##X##_OUTDEV)                                        \
-            av_register_output_format(&ff_##x##_muxer);                 \
+/* devices */
+extern AVInputFormat  ff_alsa_demuxer;
+extern AVOutputFormat ff_alsa_muxer;
+extern AVInputFormat  ff_avfoundation_demuxer;
+extern AVInputFormat  ff_bktr_demuxer;
+extern AVOutputFormat ff_caca_muxer;
+extern AVInputFormat  ff_decklink_demuxer;
+extern AVOutputFormat ff_decklink_muxer;
+extern AVInputFormat  ff_libndi_newtek_demuxer;
+extern AVOutputFormat ff_libndi_newtek_muxer;
+extern AVInputFormat  ff_dshow_demuxer;
+extern AVInputFormat  ff_fbdev_demuxer;
+extern AVOutputFormat ff_fbdev_muxer;
+extern AVInputFormat  ff_gdigrab_demuxer;
+extern AVInputFormat  ff_iec61883_demuxer;
+extern AVInputFormat  ff_jack_demuxer;
+extern AVInputFormat  ff_kmsgrab_demuxer;
+extern AVInputFormat  ff_lavfi_demuxer;
+extern AVInputFormat  ff_openal_demuxer;
+extern AVOutputFormat ff_opengl_muxer;
+extern AVInputFormat  ff_oss_demuxer;
+extern AVOutputFormat ff_oss_muxer;
+extern AVInputFormat  ff_pulse_demuxer;
+extern AVOutputFormat ff_pulse_muxer;
+extern AVOutputFormat ff_sdl2_muxer;
+extern AVInputFormat  ff_sndio_demuxer;
+extern AVOutputFormat ff_sndio_muxer;
+extern AVInputFormat  ff_v4l2_demuxer;
+extern AVOutputFormat ff_v4l2_muxer;
+extern AVInputFormat  ff_vfwcap_demuxer;
+extern AVInputFormat  ff_xcbgrab_demuxer;
+extern AVOutputFormat ff_xv_muxer;
+
+/* external libraries */
+extern AVInputFormat  ff_libcdio_demuxer;
+extern AVInputFormat  ff_libdc1394_demuxer;
+
+#include "outdev_list.c"
+#include "indev_list.c"
+
+const AVOutputFormat *av_outdev_iterate(void **opaque)
+{
+    uintptr_t i = (uintptr_t)*opaque;
+    const AVOutputFormat *f = outdev_list[i];
+    if (f)
+        *opaque = (void*)(i + 1);
+    return f;
+}
+
+const AVInputFormat *av_indev_iterate(void **opaque)
+{
+    uintptr_t i = (uintptr_t)*opaque;
+    const AVInputFormat *f = indev_list[i];
+
+    if (f)
+        *opaque = (void*)(i + 1);
+    return f;
+}
+
+#if FF_API_NEXT
+static pthread_once_t av_device_next_init = PTHREAD_ONCE_INIT;
+
+static void av_device_init_next(void)
+{
+    AVOutputFormat *prevout = NULL, *out;
+    AVInputFormat *previn = NULL, *in;
+    void *i = 0;
+    while ((out = (AVOutputFormat*)av_outdev_iterate(&i))) {
+        if (prevout)
+            prevout->next = out;
+        prevout = out;
     }
+    if (prevout)
+        prevout->next = NULL;
 
-#define REGISTER_INDEV(X, x)                                            \
-    {                                                                   \
-        extern AVInputFormat ff_##x##_demuxer;                          \
-        if (CONFIG_##X##_INDEV)                                         \
-            av_register_input_format(&ff_##x##_demuxer);                \
+    i = 0;
+    while ((in = (AVInputFormat*)av_indev_iterate(&i))) {
+        if (previn)
+            previn->next = in;
+        previn = in;
     }
+    if (previn)
+        previn->next = NULL;
+}
 
-#define REGISTER_INOUTDEV(X, x) REGISTER_OUTDEV(X, x); REGISTER_INDEV(X, x)
+void avdevice_register_all(void)
+{
+    pthread_once(&av_device_next_init, av_device_init_next);
+}
 
-static void register_all(void)
+static void *device_next(void *prev, int output,
+                         AVClassCategory c1, AVClassCategory c2)
 {
-    /* devices */
-    REGISTER_INOUTDEV(ALSA,             alsa);
-    REGISTER_INDEV   (AVFOUNDATION,     avfoundation);
-    REGISTER_INDEV   (BKTR,             bktr);
-    REGISTER_OUTDEV  (CACA,             caca);
-    REGISTER_INOUTDEV(DECKLINK,         decklink);
-    REGISTER_INOUTDEV(LIBNDI_NEWTEK,    libndi_newtek);
-    REGISTER_INDEV   (DSHOW,            dshow);
-    REGISTER_INOUTDEV(FBDEV,            fbdev);
-    REGISTER_INDEV   (GDIGRAB,          gdigrab);
-    REGISTER_INDEV   (IEC61883,         iec61883);
-    REGISTER_INDEV   (JACK,             jack);
-    REGISTER_INDEV   (KMSGRAB,          kmsgrab);
-    REGISTER_INDEV   (LAVFI,            lavfi);
-    REGISTER_INDEV   (OPENAL,           openal);
-    REGISTER_OUTDEV  (OPENGL,           opengl);
-    REGISTER_INOUTDEV(OSS,              oss);
-    REGISTER_INOUTDEV(PULSE,            pulse);
-    REGISTER_OUTDEV  (SDL2,             sdl2);
-    REGISTER_INOUTDEV(SNDIO,            sndio);
-    REGISTER_INOUTDEV(V4L2,             v4l2);
-    REGISTER_INDEV   (VFWCAP,           vfwcap);
-    REGISTER_INDEV   (XCBGRAB,          xcbgrab);
-    REGISTER_OUTDEV  (XV,               xv);
-
-    /* external libraries */
-    REGISTER_INDEV   (LIBCDIO,          libcdio);
-    REGISTER_INDEV   (LIBDC1394,        libdc1394);
+    pthread_once(&av_device_next_init, av_device_init_next);
+    const AVClass *pc;
+    AVClassCategory category = AV_CLASS_CATEGORY_NA;
+    if (!prev && !(prev = (output ? (void*)outdev_list[0] : (void*)indev_list[0])))
+        return NULL;
+
+    do {
+        if (output) {
+            if (!(prev = ((AVOutputFormat *)prev)->next))
+                break;
+            pc = ((AVOutputFormat *)prev)->priv_class;
+        } else {
+            if (!(prev = ((AVInputFormat *)prev)->next))
+                break;
+            pc = ((AVInputFormat *)prev)->priv_class;
+        }
+        if (!pc)
+            continue;
+        category = pc->category;
+    } while (category != c1 && category != c2);
+    return prev;
 }
 
-void avdevice_register_all(void)
+AVInputFormat *av_input_audio_device_next(AVInputFormat  *d)
 {
-    static AVOnce control = AV_ONCE_INIT;
+    return device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
+                       AV_CLASS_CATEGORY_DEVICE_INPUT);
+}
 
-    ff_thread_once(&control, register_all);
+AVInputFormat *av_input_video_device_next(AVInputFormat  *d)
+{
+    return device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
+                       AV_CLASS_CATEGORY_DEVICE_INPUT);
+}
+
+AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d)
+{
+    return device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
+                       AV_CLASS_CATEGORY_DEVICE_OUTPUT);
+}
+
+AVOutputFormat *av_output_video_device_next(AVOutputFormat *d)
+{
+    return device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT,
+                       AV_CLASS_CATEGORY_DEVICE_OUTPUT);
 }
+#endif
diff --git a/libavdevice/avdevice.c b/libavdevice/avdevice.c
index 72e1b67..a42d349 100644
--- a/libavdevice/avdevice.c
+++ b/libavdevice/avdevice.c
@@ -78,52 +78,6 @@ const char * avdevice_license(void)
     return LICENSE_PREFIX FFMPEG_LICENSE + sizeof(LICENSE_PREFIX) - 1;
 }
 
-static void *device_next(void *prev, int output,
-                         AVClassCategory c1, AVClassCategory c2)
-{
-    const AVClass *pc;
-    AVClassCategory category = AV_CLASS_CATEGORY_NA;
-    do {
-        if (output) {
-            if (!(prev = av_oformat_next(prev)))
-                break;
-            pc = ((AVOutputFormat *)prev)->priv_class;
-        } else {
-            if (!(prev = av_iformat_next(prev)))
-                break;
-            pc = ((AVInputFormat *)prev)->priv_class;
-        }
-        if (!pc)
-            continue;
-        category = pc->category;
-    } while (category != c1 && category != c2);
-    return prev;
-}
-
-AVInputFormat *av_input_audio_device_next(AVInputFormat  *d)
-{
-    return device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
-                       AV_CLASS_CATEGORY_DEVICE_INPUT);
-}
-
-AVInputFormat *av_input_video_device_next(AVInputFormat  *d)
-{
-    return device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
-                       AV_CLASS_CATEGORY_DEVICE_INPUT);
-}
-
-AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d)
-{
-    return device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
-                       AV_CLASS_CATEGORY_DEVICE_OUTPUT);
-}
-
-AVOutputFormat *av_output_video_device_next(AVOutputFormat *d)
-{
-    return device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT,
-                       AV_CLASS_CATEGORY_DEVICE_OUTPUT);
-}
-
 int avdevice_app_to_dev_control_message(struct AVFormatContext *s, enum AVAppToDevMessageType type,
                                         void *data, size_t data_size)
 {
diff --git a/libavdevice/avdevice.h b/libavdevice/avdevice.h
index ee94624..dd6ad93 100644
--- a/libavdevice/avdevice.h
+++ b/libavdevice/avdevice.h
@@ -66,6 +66,29 @@ const char *avdevice_configuration(void);
 const char *avdevice_license(void);
 
 /**
+ * Iterate over all registered output devices.
+ *
+ * @param opaque a pointer where libavdevice will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered output device or NULL when the iteration is
+ *         finished
+ */
+const AVOutputFormat *av_outdev_iterate(void **opaque);
+
+/**
+ * Iterate over all registered input devices.
+ *
+ * @param opaque a pointer where libavdevice will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered input device or NULL when the iteration is
+ *         finished
+ */
+const AVInputFormat *av_indev_iterate(void **opaque);
+
+#if FF_API_NEXT
+/**
  * Initialize libavdevice and register all the input and output devices.
  */
 void avdevice_register_all(void);
@@ -77,6 +100,7 @@ void avdevice_register_all(void);
  * if d is non-NULL, returns the next registered input audio/video device after d
  * or NULL if d is the last one.
  */
+attribute_deprecated
 AVInputFormat *av_input_audio_device_next(AVInputFormat  *d);
 
 /**
@@ -86,6 +110,7 @@ AVInputFormat *av_input_audio_device_next(AVInputFormat  *d);
  * if d is non-NULL, returns the next registered input audio/video device after d
  * or NULL if d is the last one.
  */
+attribute_deprecated
 AVInputFormat *av_input_video_device_next(AVInputFormat  *d);
 
 /**
@@ -95,6 +120,7 @@ AVInputFormat *av_input_video_device_next(AVInputFormat  *d);
  * if d is non-NULL, returns the next registered output audio/video device after d
  * or NULL if d is the last one.
  */
+attribute_deprecated
 AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d);
 
 /**
@@ -104,7 +130,9 @@ AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d);
  * if d is non-NULL, returns the next registered output audio/video device after d
  * or NULL if d is the last one.
  */
+attribute_deprecated
 AVOutputFormat *av_output_video_device_next(AVOutputFormat *d);
+#endif
 
 typedef struct AVDeviceRect {
     int x;      /**< x coordinate of top left corner */
diff --git a/libavdevice/version.h b/libavdevice/version.h
index 364404d..5a3246f 100644
--- a/libavdevice/version.h
+++ b/libavdevice/version.h
@@ -47,4 +47,8 @@
  * the public API and may change, break or disappear at any time.
  */
 
+#ifndef FF_API_NEXT
+#define FF_API_NEXT              (LIBAVDEVICE_VERSION_MAJOR < 59)
+#endif
+
 #endif /* AVDEVICE_VERSION_H */
-- 
2.7.4


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