av_log: mp_msg conversion

This is pretty nasty, because FFmpeg/Libav is yet another library with a
global message callback. We do something with mutexes trying to get it
done, but of course we can't actually solve this problem. If more than
one library in a process use FFmpeg/Libav, only one of them will get log
messages.

common/av_log.c

@@ -21,11 +21,16 @@
  */
 
 #include <stdlib.h>
+#include <stdio.h>
 #include <stdbool.h>
+#include <pthread.h>
 
 #include "av_log.h"
 #include "config.h"
+#include "common/common.h"
+#include "common/global.h"
 #include "common/msg.h"
+
 #include <libavutil/avutil.h>
 #include <libavutil/log.h>
 
@@ -48,6 +53,19 @@
 #include <libswresample/swresample.h>
 #endif
 
+#if LIBAVCODEC_VERSION_MICRO >= 100
+#define LIB_PREFIX "ffmpeg"
+#else
+#define LIB_PREFIX "libav"
+#endif
+
+// Needed because the av_log callback does not provide a library-safe message
+// callback.
+static pthread_mutex_t log_lock = PTHREAD_MUTEX_INITIALIZER;
+static struct mpv_global *log_mpv_instance;
+static struct mp_log *log_root, *log_decaudio, *log_decvideo, *log_demuxer;
+static bool log_print_prefix = true;
+
 static int av_log_level_to_mp_level(int av_level)
 {
     if (av_level > AV_LOG_VERBOSE)
@@ -63,17 +81,17 @@ static int av_log_level_to_mp_level(int av_level)
     return MSGL_FATAL;
 }
 
-static int extract_msg_type_from_ctx(void *ptr)
+static struct mp_log *get_av_log(void *ptr)
 {
     if (!ptr)
-        return MSGT_FIXME;
+        return log_root;
 
     AVClass *avc = *(AVClass **)ptr;
     if (!avc) {
-        mp_msg(MSGT_FIXME, MSGL_WARN,
+        mp_warn(log_root,
                "av_log callback called with bad parameters (NULL AVClass).\n"
                "This is a bug in one of Libav/FFmpeg libraries used.\n");
-        return MSGT_FIXME;
+        return log_root;
     }
 
     if (!strcmp(avc->class_name, "AVCodecContext")) {
@@ -81,59 +99,65 @@ static int extract_msg_type_from_ctx(void *ptr)
         if (s->codec) {
             if (s->codec->type == AVMEDIA_TYPE_AUDIO) {
                 if (s->codec->decode)
-                    return MSGT_DECAUDIO;
+                    return log_decaudio;
             } else if (s->codec->type == AVMEDIA_TYPE_VIDEO) {
                 if (s->codec->decode)
-                    return MSGT_DECVIDEO;
+                    return log_decvideo;
             }
-            // FIXME subtitles, encoders
-            // What msgt for them? There is nothing appropriate...
         }
-        return MSGT_FIXME;
     }
 
     if (!strcmp(avc->class_name, "AVFormatContext")) {
         AVFormatContext *s = ptr;
         if (s->iformat)
-            return MSGT_DEMUXER;
-        else if (s->oformat)
-            return MSGT_MUXER;
-        return MSGT_FIXME;
+            return log_demuxer;
     }
 
-    return MSGT_FIXME;
+    return log_root;
 }
 
-#if LIBAVCODEC_VERSION_MICRO >= 100
-#define LIB_PREFIX "ffmpeg"
-#else
-#define LIB_PREFIX "libav"
-#endif
-
-static bool print_prefix = true;
-
 static void mp_msg_av_log_callback(void *ptr, int level, const char *fmt,
                                    va_list vl)
 {
     AVClass *avc = ptr ? *(AVClass **)ptr : NULL;
     int mp_level = av_log_level_to_mp_level(level);
-    int type = extract_msg_type_from_ctx(ptr);
 
-    if (!mp_msg_test(type, mp_level))
+    // Note: mp_log is thread-safe, but destruction of the log instances is not.
+    pthread_mutex_lock(&log_lock);
+
+    if (!log_mpv_instance) {
+        pthread_mutex_unlock(&log_lock);
+        // Fallback to stderr
+        vfprintf(stderr, fmt, vl);
         return;
-
-    if (print_prefix) {
-        mp_msg(type, mp_level, "[%s/%s] ", LIB_PREFIX,
-               avc ? avc->item_name(ptr) : "?");
     }
-    print_prefix = fmt[strlen(fmt) - 1] == '\n';
 
-    mp_msg_va(type, mp_level, fmt, vl);
+    struct mp_log *log = get_av_log(ptr);
+
+    if (mp_msg_test_log(log, mp_level)) {
+        if (log_print_prefix)
+            mp_msg_log(log, mp_level, "%s: ", avc ? avc->item_name(ptr) : "?");
+        log_print_prefix = fmt[strlen(fmt) - 1] == '\n';
+
+        mp_msg_log_va(log, mp_level, fmt, vl);
+    }
+
+    pthread_mutex_unlock(&log_lock);
 }
 
-void init_libav(void)
+void init_libav(struct mpv_global *global)
 {
-    av_log_set_callback(mp_msg_av_log_callback);
+    pthread_mutex_lock(&log_lock);
+    if (!log_mpv_instance) {
+        log_mpv_instance = global;
+        log_root = mp_log_new(NULL, global->log, LIB_PREFIX);
+        log_decaudio = mp_log_new(log_root, log_root, "audio");
+        log_decvideo = mp_log_new(log_root, log_root, "video");
+        log_demuxer = mp_log_new(log_root, log_root, "demuxer");
+        av_log_set_callback(mp_msg_av_log_callback);
+    }
+    pthread_mutex_unlock(&log_lock);
+
     avcodec_register_all();
     av_register_all();
     avformat_network_init();
@@ -146,6 +170,16 @@ void init_libav(void)
 #endif
 }
 
+void uninit_libav(struct mpv_global *global)
+{
+    pthread_mutex_lock(&log_lock);
+    if (log_mpv_instance == global) {
+        log_mpv_instance = NULL;
+        talloc_free(log_root);
+    }
+    pthread_mutex_unlock(&log_lock);
+}
+
 #define V(x) (x)>>16, (x)>>8 & 255, (x) & 255
 static void print_version(struct mp_log *log, int v, char *name,
                           unsigned buildv, unsigned runv)

common/av_log.h

@@ -1,3 +1,8 @@
-void init_libav(void);
+#ifndef MP_AV_LOG_H
+#define MP_AV_LOG_H
+struct mpv_global;
 struct mp_log;
+void init_libav(struct mpv_global *global);
+void uninit_libav(struct mpv_global *global);
 void print_libav_versions(struct mp_log *log, int v);
+#endif

player/main.c

@@ -140,6 +140,7 @@ static MP_NORETURN void exit_player(struct MPContext *mpctx,
 #endif
 
     getch2_disable();
+    uninit_libav(mpctx->global);
 
     if (how != EXIT_NONE) {
         const char *reason;
@@ -310,8 +311,7 @@ static int mpv_main(int argc, char *argv[])
     struct MPOpts *opts = mpctx->opts;
     mpctx->global->opts = opts;
 
-
-    init_libav();
+    init_libav(mpctx->global);
     GetCpuCaps(&gCpuCaps);
     screenshot_init(mpctx);
     mpctx->mixer = mixer_init(mpctx, mpctx->global);