Added basic-tutorial-2 #33
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| use gst::GstObjectExt; | ||
| use gst::ElementExt; | ||
| use gst::MessageView; | ||
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Ideally you would "use gst;" and "use gst::prelude::*;" here
| } | ||
| } | ||
| else { | ||
| println!("Not all elements could be created."); |
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This else case could be at the very top and an early return from main(). Create both elements, check if both could be created and if not just error out
| }, | ||
| MessageView::Eos(..) => println!("End-Of-Stream reached."), | ||
| // We should not reach here because we only asked for ERRORs and EOS | ||
| _ => eprintln!("Unexpected message received."), |
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There is no filtered API for GstBus in the Rust bindings currently, so you would just ignore all other messages here
| // Wait until error or EOS | ||
| let bus = pipeline.get_bus().unwrap(); | ||
| if let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) { | ||
| match msg.view() { |
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Here I would "use gst::MessageView;". Check the other examples
| gst::GObjectExtManualGst::set_property_from_str( | ||
| &source, | ||
| "pattern", | ||
| "0"); |
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You can even give the pattern a name here: 0 is "smpte"
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This part is mimicking: g_object_set (source, "pattern", 0, NULL);
My understanding was that "pattern" is the property to set, and "0" is the value for that property.
Could you explain what you mean by "give the pattern a name"?
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The equivalent to the C code would be with set_property but we can do better here. Either you could use that in combination with glib::EnumClass (see playbin.rs for an example with flags, enums work very similar). That would be most explicit. Or you could use source.set_property_from_str("pattern", "smpte")
The advantage with using the string is that it is more descriptive. You don't have to look up in the docs that 0 is the SMPTE pattern but the code just says so. And you could replace it directly with e.g. " snow" without looking up the numerical value of it.
| gst::BinExtManual::add_many( | ||
| &pipeline, | ||
| &[&source, &sink]).unwrap(); | ||
| if let Err(_) = gst::ElementExt::link(&source, &sink) { |
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source.link(&sink) or gst::Element::link_many(&source, &sink)
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Also on error here, you could as well expect("Failed to link elements) instead of manually unwrapping the Result and exiting the process (same in the other places: element creation for example).
| // Build the pipeline | ||
| gst::BinExtManual::add_many( | ||
| &pipeline, | ||
| &[&source, &sink]).unwrap(); |
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pipeline.add_many(&[&source, &sink])
| eprintln!("Debugging information: {:?}", err.get_debug()); | ||
| }, | ||
| MessageView::Eos(..) => println!("End-Of-Stream reached."), | ||
| // We should not reach here because we only asked for ERRORs and EOS |
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This comment is wrong: other than in the C code, we will reach here because the filtering of messages happens in our match statement and not before that already
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| // Wait until error or EOS | ||
| let bus = pipeline.get_bus().unwrap(); | ||
| if let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) { |
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You want a loop around this to fetch all messages until EOS or Error, i.e. replace the if let with a while let and break on EOS and Error.
| @@ -29,16 +29,15 @@ fn main() { | |||
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| // Wait until error or EOS | |||
| let bus = pipeline.get_bus().unwrap(); | |||
| if let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) { | |||
| while let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) { | |||
| use gst::MessageView; | |||
| match msg.view() { | |||
| MessageView::Error(err) => { | |||
| eprintln!("Error received from element {}: {}", | |||
| msg.get_src().get_path_string(), err.get_error()); | |||
| eprintln!("Debugging information: {:?}", err.get_debug()); | |||
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On Error you also want to break. I'll fix that up and merge it, thanks!
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Oh, I completely missed that obvious part!
Thank you for all your feedback, it's super helpful!
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I'm glad to hear that it was useful for you :) Thanks again for this PR, it's merged now
Contributes to solve #32.
I have never used gstreamer-rs before, so I'm not entirely sure if this is correct.
It compiles, runs and prints "Unexpected message received."