On Sat, Nov 20, 2021 at 2:01 PM José María García Pérez < josemaria.alk...@gmail.com> wrote:
> There are a few things under the hood: > 1. I have several `connect` functions which have different type signatures: > - For filter: > https://github.com/mantielero/mlt.nim/blob/51245b9fea6ad1555687ff9229c66ca17a6d3ffb/src/lib/filter.nim#L5-L8 > - For consumer: > https://github.com/mantielero/mlt.nim/blob/51245b9fea6ad1555687ff9229c66ca17a6d3ffb/src/lib/consumer.nim#L30-L33 > For this functions, I just map: `mlt_filter_connect` with the equivalent > signature. > Oh, that is designed more for use in multitrack scenarios, but I guess that works. I kind of forgot about it, because it is mainly used by mlt_field_plant_filter(), which is the more commonly used function in multitrack command lines, for example, `melt -filter`. > 2. Given that they work with Service, I just create a number of > converters. In nim converters, are used to change type automatically. You > can see for example the following which coverts from Producer to Service > automatically: > > https://github.com/mantielero/mlt.nim/blob/51245b9fea6ad1555687ff9229c66ca17a6d3ffb/src/lib/producer.nim#L8-L10 > This enables using a `Producer` directly with the `connect` function > without the need of getting previously the Service (that is done > implicitly). > 3. I just create the `>` operators in a way that for me make more sense > visually: from the producer to the consumer. They just call `connect`. > > I have wrapped the `mlt_service_attach` function (I wasn't aware of it). > So now, the following works as well: > This corresponds to the `melt -attach` option, and Shotcut uses only this approach even in multitrack scenarios - attaching to clips, consumer, and playlists that represent tracks. > ``` > clip.attach( filter ) > clip > sdl > ``` > > https://github.com/mantielero/mlt.nim/blob/master/examples/ex05_filter_frei0r_attach.nim > > > PS: sorry if the wording is not right. I am not a pro developer. > Regards, > José M. > > El sáb, 20 nov 2021 a las 20:34, Dan Dennedy (<d...@dennedy.org>) escribió: > >> Thanks for sharing that. Read more below... >> >> On Sat, Nov 20, 2021 at 8:54 AM José María García Pérez < >> josemaria.alk...@gmail.com> wrote: >> >>> I implemented some examples in the Nim programming language. Nim >>> compiles into C (among other languages). >>> >>> I like that it gives you the feeling of python despite it is using >>> actual types. >>> >>> The code looks as follows: >>> ``` >>> import mlt, os >>> var f = initFactory() >>> >>> # Create the default consumer >>> var p = newProfile() >>> var sdl = newFactoryConsumer(p, "sdl2") >>> >>> # Create via the default producer >>> var clip = newFactoryProducer(p, resource = >>> "avformat:/home/jose/Descargas/sygic.mp4") >>> >>> var filter = newFactoryFilter(p, "frei0r.pixeliz0r") >>> filter["BlockSizeX"] = 0.1 >>> filter["BlockSizeY"] = 0.2 >>> >>> clip > filter >>> filter > sdl >>> >>> >> >> So, the > operator is mapped to both mlt_service_connect_producer() and >> mlt_service_attach()? I do not understand how the sdl consumer is >> connecting to the filter because the filter should be *attached* to the >> producer, and the consumer *connected* to the producer. >> >> >> >>> # Start the consumer >>> sdl.start >>> >>> while not sdl.stopped: >>> sleep(1) >>> ``` >>> As I said, it compiles to C. If compiled in release mode, the executable >>> only takes 115kb. >>> >>> This is just a starting point. You can see some more examples here: >>> https://github.com/mantielero/mlt.nim/tree/master/examples >>> >>> Regards, >>> José María >>> >>>
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