Re: [Mlt-devel] Question about decklink producer

[Dan D. <da...@de...>]

On Fri, May 27, 2011 at 4:12 PM, j-b-m <j-...@us...> wrote:
> Hi.
>
> I made a few tests with the Decklink producer, using an Intensity Pro card. I
> can correctly preview the video:
>
> melt -profile atsc_1080i_50 decklink:0
>
> However, when I try to encode the stream using an avformat consumer, the
> process quickly eats all my memory (goes up to more than 1 Giga in 20 seconds)
> and then freezes my system.

I did not test this yet, but did a brief review and saw something. The
producer has a buffer queue between the decklink and MLT threads. This
defaults to a max of 25 frames, but when it overflows because they are
not consumed fast enough, it appears the frame is not closed. I think
this should fix it.

diff --git a/src/modules/decklink/producer_decklink.cpp
b/src/modules/decklink/producer_decklink.cpp
index 5bd6ea3..6d327ab 100644
--- a/src/modules/decklink/producer_decklink.cpp
+++ b/src/modules/decklink/producer_decklink.cpp
@@ -306,6 +306,8 @@ public:
 				mlt_deque_push_back( m_queue, frame );
 				pthread_cond_broadcast( &m_condition );
 			}
+			else
+				mlt_frame_close( frame );
 			pthread_mutex_unlock( &m_mutex );
 		}



> I used the following command to encode:
>
> melt -profile atsc_1080i_50 decklink:0 -consumer avformat:test.mpg
> vcodec=mpeg2video minrate=0 b=6000k acodec=mp2 ab=128k ar=48000
>
> I tried a few other encoding params without more success. Any ideas? Is it

When encoding HD, you probably want to add threads=2 or more.

> because encoding is too slow and MLT caches more and more frames? Did anybody
> succeed in capturing from the decklink producer to a file?
>
> regards
> jb
>
-- 
+-DRD-+