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active_call/media/track/
track_codec.rs

1use crate::{media::AudioFrame, media::PcmBuf, media::Samples};
2use audio_codec::{
3    CodecType, Decoder, Encoder, Resampler, bytes_to_samples,
4    g722::{G722Decoder, G722Encoder},
5    pcma::{PcmaDecoder, PcmaEncoder},
6    pcmu::{PcmuDecoder, PcmuEncoder},
7    samples_to_bytes,
8};
9use std::collections::HashMap;
10
11use audio_codec::g729::{G729Decoder, G729Encoder};
12#[cfg(feature = "opus")]
13use audio_codec::opus::{OpusDecoder, OpusEncoder};
14
15pub struct TrackCodec {
16    pcmu_encoder: PcmuEncoder,
17    pcmu_decoder: PcmuDecoder,
18    pcma_encoder: PcmaEncoder,
19    pcma_decoder: PcmaDecoder,
20
21    g722_encoder: Option<Box<G722Encoder>>,
22    g722_decoder: Option<Box<G722Decoder>>,
23
24    g729_encoder: Option<Box<G729Encoder>>,
25    g729_decoder: Option<Box<G729Decoder>>,
26
27    #[cfg(feature = "opus")]
28    opus_encoder: Option<OpusEncoder>,
29    #[cfg(feature = "opus")]
30    opus_decoder: Option<OpusDecoder>,
31
32    resampler: Option<Resampler>,
33    resampler_in_rate: u32,
34    resampler_out_rate: u32,
35    pub payload_type_map: HashMap<u8, CodecType>,
36}
37
38impl Clone for TrackCodec {
39    fn clone(&self) -> Self {
40        let mut new = Self::new();
41        new.payload_type_map = self.payload_type_map.clone();
42        new
43    }
44}
45
46impl TrackCodec {
47    pub fn new() -> Self {
48        let mut payload_type_map = HashMap::new();
49        payload_type_map.insert(0, CodecType::PCMU);
50        payload_type_map.insert(8, CodecType::PCMA);
51        payload_type_map.insert(9, CodecType::G722);
52        payload_type_map.insert(18, CodecType::G729);
53        payload_type_map.insert(101, CodecType::TelephoneEvent);
54        payload_type_map.insert(111, CodecType::Opus);
55
56        Self {
57            pcmu_encoder: PcmuEncoder::new(),
58            pcmu_decoder: PcmuDecoder::new(),
59            pcma_encoder: PcmaEncoder::new(),
60            pcma_decoder: PcmaDecoder::new(),
61            g722_encoder: None,
62            g722_decoder: None,
63            g729_encoder: None,
64            g729_decoder: None,
65            #[cfg(feature = "opus")]
66            opus_encoder: None,
67            #[cfg(feature = "opus")]
68            opus_decoder: None,
69            resampler: None,
70            resampler_in_rate: 0,
71            resampler_out_rate: 0,
72            payload_type_map,
73        }
74    }
75
76    pub fn set_payload_type(&mut self, pt: u8, codec: CodecType) {
77        self.payload_type_map.insert(pt, codec);
78    }
79
80    pub fn is_audio(payload_type: u8) -> bool {
81        match payload_type {
82            0 | 8 | 9 | 18 | 111 => true,
83            101 => false, // Telephone Event (DTMF) should not be decoded as audio
84            pt if pt >= 96 && pt <= 127 => true,
85            _ => false,
86        }
87    }
88
89    pub fn decode(
90        &mut self,
91        payload_type: u8,
92        payload: &[u8],
93        target_sample_rate: u32,
94    ) -> (u32, u16, PcmBuf) {
95        let codec = self
96            .payload_type_map
97            .get(&payload_type)
98            .cloned()
99            .unwrap_or_else(|| match payload_type {
100                0 => CodecType::PCMU,
101                8 => CodecType::PCMA,
102                9 => CodecType::G722,
103                18 => CodecType::G729,
104                111 => CodecType::Opus,
105                _ => CodecType::PCMU,
106            });
107
108        let pcm = match codec {
109            CodecType::PCMU => self.pcmu_decoder.decode(payload),
110            CodecType::PCMA => self.pcma_decoder.decode(payload),
111            CodecType::G722 => self
112                .g722_decoder
113                .get_or_insert_with(|| Box::new(G722Decoder::new()))
114                .decode(payload),
115            CodecType::G729 => self
116                .g729_decoder
117                .get_or_insert_with(|| Box::new(G729Decoder::new()))
118                .decode(payload),
119            #[cfg(feature = "opus")]
120            CodecType::Opus => self
121                .opus_decoder
122                .get_or_insert_with(OpusDecoder::new_default)
123                .decode(payload),
124            _ => bytes_to_samples(payload),
125        };
126
127        let (in_rate, channels) = match codec {
128            CodecType::PCMU => (8000, 1),
129            CodecType::PCMA => (8000, 1),
130            CodecType::G722 => (16000, 1),
131            CodecType::G729 => (8000, 1),
132            #[cfg(feature = "opus")]
133            CodecType::Opus => {
134                if pcm.len() >= 1920 {
135                    (48000, 2)
136                } else {
137                    (48000, 1)
138                }
139            }
140            _ => (8000, 1),
141        };
142
143        (
144            target_sample_rate,
145            channels,
146            self.resample(pcm, in_rate, target_sample_rate),
147        )
148    }
149
150    pub fn resample(&mut self, pcm: PcmBuf, in_rate: u32, out_rate: u32) -> PcmBuf {
151        if in_rate == out_rate {
152            return pcm;
153        }
154
155        if self.resampler.is_none()
156            || self.resampler_in_rate != in_rate
157            || self.resampler_out_rate != out_rate
158        {
159            self.resampler = Some(Resampler::new(in_rate as usize, out_rate as usize));
160            self.resampler_in_rate = in_rate;
161            self.resampler_out_rate = out_rate;
162        }
163        self.resampler.as_mut().unwrap().resample(&pcm)
164    }
165
166    pub fn encode(&mut self, payload_type: u8, frame: AudioFrame) -> (u8, Vec<u8>) {
167        match frame.samples {
168            Samples::PCM { samples: mut pcm } => {
169                let target_samplerate = match payload_type {
170                    0 => 8000,
171                    8 => 8000,
172                    9 => 16000,
173                    18 => 8000,
174                    111 => 48000, // Opus sample rate
175                    _ => 8000,
176                };
177
178                if frame.sample_rate != target_samplerate {
179                    if self.resampler.is_none()
180                        || self.resampler_in_rate != frame.sample_rate
181                        || self.resampler_out_rate != target_samplerate
182                    {
183                        self.resampler = Some(Resampler::new(
184                            frame.sample_rate as usize,
185                            target_samplerate as usize,
186                        ));
187                        self.resampler_in_rate = frame.sample_rate;
188                        self.resampler_out_rate = target_samplerate;
189                    }
190                    pcm = self.resampler.as_mut().unwrap().resample(&pcm);
191                }
192
193                let payload = match payload_type {
194                    0 => self.pcmu_encoder.encode(&pcm),
195                    8 => self.pcma_encoder.encode(&pcm),
196                    9 => self
197                        .g722_encoder
198                        .get_or_insert_with(|| Box::new(G722Encoder::new()))
199                        .encode(&pcm),
200                    18 => self
201                        .g729_encoder
202                        .get_or_insert_with(|| Box::new(G729Encoder::new()))
203                        .encode(&pcm),
204                    #[cfg(feature = "opus")]
205                    111 => self
206                        .opus_encoder
207                        .get_or_insert_with(OpusEncoder::new_default)
208                        .encode(&pcm),
209                    _ => samples_to_bytes(&pcm),
210                };
211                (payload_type, payload)
212            }
213            Samples::RTP {
214                payload_type,
215                payload,
216                ..
217            } => (payload_type, payload),
218            _ => (payload_type, vec![]),
219        }
220    }
221}