mmal/vout: Use fixed binding of mmal buffer to picture

Instead of dynamically allocating a mmal buffer from the mmal buffer pool use
a fixed binding, where the same mmal buffer is used for the whole pictures
lifecycle. This avoids some overhead on picture allocation and simplifies the
code. As the mmal buffer pool is allocated in exactly the same size as the vlc
picture pool there is no drawback doing it this way.
Signed-off-by: Julian Scheel <julian@jusst.de>
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/hw/mmal/mmal_picture.c

@@ -30,43 +30,14 @@
 int mmal_picture_lock(picture_t *picture)
 {
     picture_sys_t *pic_sys = picture->p_sys;
-    int ret = VLC_SUCCESS;
-
-    vlc_mutex_lock(pic_sys->mutex);
-
-    MMAL_BUFFER_HEADER_T *buffer = mmal_queue_timedwait(pic_sys->queue, 2);
-    if (!buffer) {
-        ret = VLC_EGENERIC;
-        goto out;
-    }
+    MMAL_BUFFER_HEADER_T *buffer = pic_sys->buffer;
 
-    mmal_buffer_header_reset(buffer);
     buffer->user_data = picture;
     picture->p[0].p_pixels = buffer->data;
     picture->p[1].p_pixels += (ptrdiff_t)buffer->data;
     picture->p[2].p_pixels += (ptrdiff_t)buffer->data;
 
-    pic_sys->buffer = buffer;
-
     pic_sys->displayed = false;
 
-out:
-    vlc_mutex_unlock(pic_sys->mutex);
-    return ret;
-}
-
-void mmal_picture_unlock(picture_t *picture)
-{
-    picture_sys_t *pic_sys = picture->p_sys;
-    MMAL_BUFFER_HEADER_T *buffer = pic_sys->buffer;
-
-    vlc_mutex_lock(pic_sys->mutex);
-
-    pic_sys->buffer = NULL;
-    if (buffer) {
-        buffer->user_data = NULL;
-        mmal_buffer_header_release(buffer);
-    }
-
-    vlc_mutex_unlock(pic_sys->mutex);
+    return VLC_SUCCESS;
 }

modules/hw/mmal/mmal_picture.h

@@ -34,13 +34,9 @@ struct picture_sys_t {
     vlc_object_t *owner;
 
     MMAL_BUFFER_HEADER_T *buffer;
-    MMAL_QUEUE_T *queue;
-    vlc_mutex_t *mutex;
     bool displayed;
 };
 
-vlc_mutex_t* get_mmal_opaque_mutex(void);
 int mmal_picture_lock(picture_t *picture);
-void mmal_picture_unlock(picture_t *picture);
 
 #endif

modules/hw/mmal/vout.c

@@ -351,8 +351,10 @@ static void Close(vlc_object_t *object)
         picture_pool_Release(sys->picture_pool);
     else
         for (i = 0; i < sys->num_buffers; ++i)
-            if (sys->pictures[i])
+            if (sys->pictures[i]) {
+                mmal_buffer_header_release(sys->pictures[i]->p_sys->buffer);
                 picture_Release(sys->pictures[i]);
+            }
 
     vlc_mutex_destroy(&sys->buffer_mutex);
     vlc_cond_destroy(&sys->buffer_cond);
@@ -497,8 +499,7 @@ static picture_pool_t *vd_pool(vout_display_t *vd, unsigned count)
     for (i = 0; i < sys->num_buffers; ++i) {
         picture_res.p_sys = calloc(1, sizeof(picture_sys_t));
         picture_res.p_sys->owner = (vlc_object_t *)vd;
-        picture_res.p_sys->queue = sys->pool->queue;
-        picture_res.p_sys->mutex = &sys->buffer_mutex;
+        picture_res.p_sys->buffer = mmal_queue_get(sys->pool->queue);
 
         sys->pictures[i] = picture_NewFromResource(&fmt, &picture_res);
         if (!sys->pictures[i]) {
@@ -515,7 +516,6 @@ static picture_pool_t *vd_pool(vout_display_t *vd, unsigned count)
     picture_pool_cfg.picture_count = sys->num_buffers;
     picture_pool_cfg.picture = sys->pictures;
     picture_pool_cfg.lock = mmal_picture_lock;
-    picture_pool_cfg.unlock = mmal_picture_unlock;
 
     sys->picture_pool = picture_pool_NewExtended(&picture_pool_cfg);
     if (!sys->picture_pool) {