1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165

use crate::media_stream::GStreamerMediaStream;
use gst;
use gst::caps::NoFeature;
use gst::prelude::*;
use servo_media_streams::capture::*;
use servo_media_streams::registry::MediaStreamId;
use servo_media_streams::MediaStreamType;
use std::i32;

trait AddToCaps {
    type Bound;
    fn add_to_caps(
        &self,
        name: &str,
        min: Self::Bound,
        max: Self::Bound,
        builder: gst::caps::Builder<NoFeature>,
    ) -> Option<gst::caps::Builder<NoFeature>>;
}

impl AddToCaps for Constrain<u32> {
    type Bound = u32;
    fn add_to_caps(
        &self,
        name: &str,
        min: u32,
        max: u32,
        builder: gst::caps::Builder<NoFeature>,
    ) -> Option<gst::caps::Builder<NoFeature>> {
        match self {
            Constrain::Value(v) => Some(builder.field(name, v)),
            Constrain::Range(r) => {
                let min = into_i32(r.min.unwrap_or(min));
                let max = into_i32(r.max.unwrap_or(max));
                let range = gst::IntRange::<i32>::new(min, max);

                // TODO: Include the ideal caps value in the caps, needs a refactor
                //       of the AddToCaps trait
                Some(builder.field(name, range))
            }
        }
    }
}

fn into_i32(x: u32) -> i32 {
    if x > i32::MAX as u32 {
        i32::MAX
    } else {
        x as i32
    }
}

impl AddToCaps for Constrain<f64> {
    type Bound = i32;
    fn add_to_caps<'a>(
        &self,
        name: &str,
        min: i32,
        max: i32,
        builder: gst::caps::Builder<NoFeature>,
    ) -> Option<gst::caps::Builder<NoFeature>> {
        match self {
            Constrain::Value(v) => Some(builder.field("name", gst::Fraction::approximate_f64(*v)?)),
            Constrain::Range(r) => {
                let min = r
                    .min
                    .and_then(gst::Fraction::approximate_f64)
                    .unwrap_or(gst::Fraction::new(min, 1));
                let max = r
                    .max
                    .and_then(gst::Fraction::approximate_f64)
                    .unwrap_or(gst::Fraction::new(max, 1));
                let range = gst::FractionRange::new(min, max);
                // TODO: Include the ideal caps value in the caps, needs a refactor
                //       of the AddToCaps trait
                Some(builder.field(name, range))
            }
        }
    }
}

// TODO(Manishearth): Should support a set of constraints
fn into_caps(set: MediaTrackConstraintSet, format: &str) -> Option<gst::Caps> {
    let mut builder = gst::Caps::builder(format);
    if let Some(w) = set.width {
        builder = w.add_to_caps("width", 0, 1000000, builder)?;
    }
    if let Some(h) = set.height {
        builder = h.add_to_caps("height", 0, 1000000, builder)?;
    }
    if let Some(aspect) = set.aspect {
        builder = aspect.add_to_caps("pixel-aspect-ratio", 0, 1000000, builder)?;
    }
    if let Some(fr) = set.frame_rate {
        builder = fr.add_to_caps("framerate", 0, 1000000, builder)?;
    }
    if let Some(sr) = set.sample_rate {
        builder = sr.add_to_caps("rate", 0, 1000000, builder)?;
    }
    Some(builder.build())
}

struct GstMediaDevices {
    monitor: gst::DeviceMonitor,
}

impl GstMediaDevices {
    pub fn new() -> Self {
        Self {
            monitor: gst::DeviceMonitor::new(),
        }
    }

    pub fn get_track(
        &self,
        video: bool,
        constraints: MediaTrackConstraintSet,
    ) -> Option<GstMediaTrack> {
        let (format, filter) = if video {
            ("video/x-raw", "Video/Source")
        } else {
            ("audio/x-raw", "Audio/Source")
        };
        let caps = into_caps(constraints, format)?;
        let f = self.monitor.add_filter(Some(filter), Some(&caps));
        let devices = self.monitor.devices();
        if let Some(f) = f {
            let _ = self.monitor.remove_filter(f);
        }
        if let Some(d) = devices.front() {
            let element = d.create_element(None).ok()?;
            Some(GstMediaTrack { element })
        } else {
            None
        }
    }
}

pub struct GstMediaTrack {
    element: gst::Element,
}

fn create_input_stream(
    stream_type: MediaStreamType,
    constraint_set: MediaTrackConstraintSet,
) -> Option<MediaStreamId> {
    let devices = GstMediaDevices::new();
    devices
        .get_track(stream_type == MediaStreamType::Video, constraint_set)
        .map(|track| {
            let f = match stream_type {
                MediaStreamType::Audio => GStreamerMediaStream::create_audio_from,
                MediaStreamType::Video => GStreamerMediaStream::create_video_from,
            };
            f(track.element)
        })
}

pub fn create_audioinput_stream(constraint_set: MediaTrackConstraintSet) -> Option<MediaStreamId> {
    create_input_stream(MediaStreamType::Audio, constraint_set)
}

pub fn create_videoinput_stream(constraint_set: MediaTrackConstraintSet) -> Option<MediaStreamId> {
    create_input_stream(MediaStreamType::Video, constraint_set)
}