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Media Lovin' Toolkit

MLT is an open source multimedia framework, designed and developed for television broadcasting. It provides a toolkit for broadcasters, video editors, media players, transcoders, web streamers and many more types of applications. The functionality of the system is provided via an assortment of ready to use tools, XML authoring components, and an extensible plug-in based API.

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YADIF: Since its inception, MLT has been limping along on linear-blending for deinterlacing, but I just added the world-class YADIF deinterlace filter! It is not a new MLT filter that you need to manually apply; rather, it is integrated with the existing one. It is the new default when you are not playing through SDL (i.e. Kdenlive and OpenShot). SDL defaults to linear interpolation (i.e. onefield), which is faster and will not making seeking on AVCHD suck any more than it already does. Encoding through avformat and SDI outputs default to YADIF (which, of course, gets applied only when required).

This took quite a bit of work because this filter requires the preceding and following frames' images to the current frame being processed, and the framework was not equipped to provide that. Also, there were quite a few pitfalls along the way.
(Fri, 05 Feb 2010 05:03:48 GMT)
MLT v0.4.10 released: Yesterday, I introduced a fatal bug shortly before the 0.4.8 release. Actually, a bug fix exposed a different bug. So, this release is a "hot fix" release.
(Wed, 09 Dec 2009 04:44:39 GMT)
MLT v0.4.8 released: This is mainly a maintenance release. Besides bug fixes here are other
notable changes.

modules:
* avformat producer:
- refactored producer to use much less properties
- added support for audio_index=all for linsys_sdi consumer
- added force_fps property (does yet not adjust duration)
* core/crop: added "center" property to crop filter
* linsys_sdi:
- added support for >2 audio channels
- added property meta.map.audio.<N>.channels=<integer>
- added property meta.map.audio.<N>.start=<integer>
* qimage/kdenlivetitle: add typewriter effect
(Tue, 08 Dec 2009 08:00:01 GMT)
VDPAU: Last week I added support for VDPAU decoding of H.264. This is working and stable, but it is not yet pushed to the public Git repository. Currently, one can only load about 10-20 AVCHD clips - depending upon video memory. I have to refactor the FFmpeg (avformat) module to take advantage of the new LRU mlt_cache. Previously, this was difficult due to all the numerous properties it was using. Well, just after the 0.4.6 release, I had refactored it to use a mlt_producer child structure. This was done partly to be more efficient and gave me an opportunity to have a thorough re-review of this code before embarking on a major change I promised in exchange for getting the Linsys SDI consumer as open source and a card with which to test it. I know; I am rambling. The point is that it should be fairly easy to now make it use the cache, which means it will also be possible to support hundreds of clips in a project with random access. (Previously, hundreds could only be supported for sequential access by usage of the autoclose=1 property on the playlist object.)

Whew! OK, now for the not-so-great part. I was hoping this could give a good performance boost especially for seeking as that took a major hit in performance in 0.4.6 in exchange for accuracy and quality. Unfortunately, on my MacBook Pro with a Geforce 8600M GT, I am only seeing about a one second improvement in seek performance and this is without disabling the in-loop deblocking filter on the CPU test. I see about 33% improvement in time to simply decode frames as-fast-as-possible and about a 10% reduction in CPU utilization during real-time playback. Why is this? Well for one, MLT uses packed 4:2:2 for its Y'CbCr colorspace and even though the API seems to indicate it can provide this, neither of my 2 systems that can support VDPAU can provide this. Therefore, it must still do a colorspace conversion on the CPU. The overhead of sending the bitstream to the GPU and especially receiving the uncompressed decoded image back into system memory seems to counter-compensate the gains provided by the GPU. I do plan to keep this code and try to integrate the deinterlacer and perhaps some other filters to make it more compelling. However, it means I am going to wait until after today's release to further it and make it available.
(Mon, 30 Nov 2009 17:56:27 GMT)
v0.4.6 released: This release is an enhancement release along with numerous build, A/V synch, concurrency, and other bug fixes.

configure: new option --avformat-svn-version

modules:
* avformat: much improved seeking on H.264/MPEG2-TS (AVCHD) (Ivan Schreter)
* core: new imageconvert and audioconvert filters (framework refactorization)
* linsys: new SDI consumer (Broadcast Centre Europe)
* qimage: new kdenlivetitle producer (J.B. Mardelle and Marco Gittler)
* sdl: new audio_only consumer for OS X

mlt++ and swig: update bindings

framework:
* refactored image format conversion
mlt_frame.h:
- added convert_image() virtual function
- added mlt_image_format_name()
- removed many mlt_convert_ and scaling/padding functions
* refactored audio format conversion
mlt_frame.h:
- mlt_get_audio() virtual function parameters changed
- added convert_audio() virtual function
- mlt_frame_get_audio() parameters changed
- added mlt_frame_set_audio()
- added mlt_audio_format_name()
mlt_types.h:
- deprecated mlt_audio_pcm
- added mlt_audio_s16
- added mlt_audio_s32
- added mlt_audio_float
(Wed, 07 Oct 2009 08:03:42 GMT)

Topic revision: r32 - 2009-11-13 - 09:10:26 - DanDennedy

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