lavc: enable recursively using avcodec_open2/close.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/internal.h

@@ -178,4 +178,16 @@ int ff_get_logical_cpus(AVCodecContext *avctx);
 
 int avpriv_h264_has_num_reorder_frames(AVCodecContext *avctx);
 
+/**
+ * Call avcodec_open2 recursively by decrementing counter, unlocking mutex,
+ * calling the function and then restoring again. Assumes the mutex is
+ * already locked
+ */
+int ff_codec_open2_recursive(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
+
+/**
+ * Call avcodec_close recursively, counterpart to avcodec_open2_recursive.
+ */
+int ff_codec_close_recursive(AVCodecContext *avctx);
+
 #endif /* AVCODEC_INTERNAL_H */

libavcodec/utils.c

@@ -798,6 +798,27 @@ int attribute_align_arg avcodec_open(AVCodecContext *avctx, AVCodec *codec)
 }
 #endif
 
+int attribute_align_arg ff_codec_open2_recursive(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
+{
+    int ret = 0;
+
+    entangled_thread_counter--;
+    /* Release any user-supplied mutex. */
+    if (ff_lockmgr_cb) {
+        (*ff_lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE);
+    }
+
+    ret = avcodec_open2(avctx, codec, options);
+
+    /* If there is a user-supplied mutex locking routine, call it. */
+    if (ff_lockmgr_cb) {
+        if ((*ff_lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
+            return -1;
+    }
+    entangled_thread_counter++;
+    return ret;
+}
+
 int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
 {
     int ret = 0;
@@ -1809,6 +1830,27 @@ void avsubtitle_free(AVSubtitle *sub)
     memset(sub, 0, sizeof(AVSubtitle));
 }
 
+av_cold int ff_codec_close_recursive(AVCodecContext *avctx)
+{
+    int ret = 0;
+
+    entangled_thread_counter--;
+    /* Release any user-supplied mutex. */
+    if (ff_lockmgr_cb) {
+        (*ff_lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE);
+    }
+
+    ret = avcodec_close(avctx);
+
+    /* If there is a user-supplied mutex locking routine, call it. */
+    if (ff_lockmgr_cb) {
+        if ((*ff_lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
+            return -1;
+    }
+    entangled_thread_counter++;
+    return ret;
+}
+
 av_cold int avcodec_close(AVCodecContext *avctx)
 {
     /* If there is a user-supplied mutex locking routine, call it. */