New, also help on dealing with multiple audio streams using gstreamer-rs

[Michael Johnson]

Oh wait I see what you mean about the first point. My eyes can't see a
minus sign apparently :P



On Thu, 17 Dec 2020, 13:49 Michael Johnson, <liquidmikerrs at gmail.com> wrote:

> All those warnings are related to not handling the None type, I didn't
> think that would have any bearing.
>
> Wait. You're not supposed to use emit? Then why does it exist? Surely you
> emit a signal to then be caught by the connect. By the logic of setting the
> value of 2 every them then current audio should go -1,-1,2 not -1,-1,-1. It
> yields 2 on exit. Which was my point
>
> What is the alternative to using emit then, and why does the alternative
> still relate to connect?
>
> On Thu, 17 Dec 2020, 13:36 Sebastian Dröge, <sebastian at centricular.com>
> wrote:
>
>> On Thu, 2020-12-17 at 12:28 +0000, Michael Johnson wrote:
>>
>> As requested a toy example,
>> Here we see that the audio-changed emit never activates the connect,
>> maybe because it emits before the video has began playing?
>>
>> I'm probably doing something very wrong
>>
>>
>> Yeah, you're ignoring compiler warnings here that tell you that you're
>> ignoring potential errors :)
>>
>> Make sure to at least `unwrap()` `Result`s instead of ignoring them, then
>> you immediately know if you did something wrong there.
>> In this case the emitting of the "audio-changed" signal fails because of
>> the wrong number of arguments.
>>
>> But that also doesn't matter here: that signal is supposed to be emitted
>> by playbin whenever something changes, not by you.
>>
>> After removing that line what I get is
>>
>> current audio track is -1
>> number of audio tracks is 1
>> current audio track is -1
>> number of audio tracks is 2
>> current audio track is -1
>> number of audio tracks is 3
>>
>> That looks as expected. Every signal emission you're setting the current
>> audio track to 2, but only the last time there actually is a 3rd (0, 1, 2)
>> audio track available.
>> So in the end it should use the 3rd audio track.
>>
>> If you change it for example to set it to 1 then you'll see that during
>> the last signal emission the current audio track is 1.
>>
>>
>> For getting state into the signal handler closure, take a look at the
>> overlay-composition.rs example and what it does with the DrawingContext
>> inside the Arc<Mutex<_>> there.
>>
>> --
>>
>> Sebastian Dröge, Centricular Ltd · https://www.centricular.com
>> <http://www.centricular.com>
>>
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
>
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