Commit b24f6287 authored by Thijs Vermeir's avatar Thijs Vermeir Committed by Sebastian Dröge
parent e1d134c4
extern crate gstreamer as gst;
use gst::prelude::*;
use gst::MessageView;
fn print_caps(caps: gst::Caps, prefix: &str) {
if caps.is_any() {
println!("{}ANY", prefix);
return;
}
if caps.is_empty() {
println!("{}EMPTY", prefix);
return;
}
for structure in caps.iter() {
println!("{}{}", prefix, structure.get_name());
for (field, value) in structure.iter() {
println!("{} {}:{:?}", prefix, field, value);
}
}
}
// Prints information about a Pad Template, including its Capabilitites
fn print_pad_template_information(factory: &gst::ElementFactory) {
let long_name = factory
.get_metadata("long-name")
.expect("Failed to get long-name of element factory.");
println!("Pad Template for {}:", long_name);
if factory.get_num_pad_templates() == 0u32 {
println!(" None");
return;
}
for pad_template in factory.get_static_pad_templates() {
if pad_template.direction() == gst::PadDirection::Src {
println!(" SRC template: '{}'", pad_template.name_template());
} else if pad_template.direction() == gst::PadDirection::Sink {
println!(" SINK template: '{}'", pad_template.name_template());
} else {
println!(" UNKNOWN!!! template: '{}'", pad_template.name_template());
}
if pad_template.presence() == gst::PadPresence::Always {
println!(" Availability: Always");
} else if pad_template.presence() == gst::PadPresence::Sometimes {
println!(" Availability: Sometimes");
} else if pad_template.presence() == gst::PadPresence::Request {
println!(" Availability: On request");
} else {
println!(" Availability: UNKNOWN!!!");
}
let caps = pad_template.get_caps();
println!(" Capabilities:");
print_caps(caps, " ");
}
}
fn print_pad_capabilities(element: &gst::Element, pad_name: &str) {
let pad = element
.get_static_pad(pad_name)
.expect("Could not retrieve pad");
println!("Caps for the {} pad:", pad_name);
match pad.get_current_caps() {
Some(caps) => {
print_caps(caps, " ");
}
None => {
let caps = pad.query_caps(None).expect("Failed to query caps on pad");
print_caps(caps, " ");
}
}
}
fn main() {
// Initialize GStreamer
gst::init().unwrap();
// Create the element factories
let source_factory =
gst::ElementFactory::find("audiotestsrc").expect("Failed to create audiotestsrc factory.");
let sink_factory = gst::ElementFactory::find("autoaudiosink")
.expect("Failed to create autoaudiosink factory.");
// Print information about the pad templates of these factories
print_pad_template_information(&source_factory);
print_pad_template_information(&sink_factory);
// Ask the factories to instantiate actual elements
let source = source_factory
.create("source")
.expect("Failed to create source element");
let sink = sink_factory
.create("sink")
.expect("Failed to create sink element");
// Create the empty pipeline
let pipeline = gst::Pipeline::new("test-pipeline");
pipeline.add_many(&[&source, &sink]).unwrap();
source.link(&sink).expect("Elements could not be linked.");
// Print initial negotiated caps (in NULL state)
println!("In NULL state:");
print_pad_capabilities(&sink, "sink");
// Start playing
let ret = pipeline.set_state(gst::State::Playing);
if ret == gst::StateChangeReturn::Failure {
eprintln!(
"Unable to set the pipeline to the playing state (check the bus for error messages)."
)
}
// Wait until error, EOS or State Change
let bus = pipeline.get_bus().unwrap();
loop {
let msg = bus.timed_pop(gst::CLOCK_TIME_NONE);
match msg {
Some(msg) => {
match msg.view() {
MessageView::Error(err) => {
println!(
"Error received from element {}: {} ({:?})",
msg.get_src().get_path_string(),
err.get_error(),
err.get_debug()
);
break;
}
MessageView::Eos(..) => {
println!("End-Of-Stream reached.");
break;
}
MessageView::StateChanged(state) =>
// We are only interested in state-changed messages from the pipeline
if msg.get_src() == pipeline {
let new_state = state.get_current();
let old_state = state.get_old();
println!(
"Pipeline state changed from {:?} to {:?}",
old_state,
new_state
);
print_pad_capabilities(&sink, "sink");
},
_ => (),
}
}
None => (),
}
}
// Shutdown pipeline
let ret = pipeline.set_state(gst::State::Null);
assert_ne!(ret, gst::StateChangeReturn::Failure);
}
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