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1 | //! Audio output in WAV format. | |
2 | use crate::io::byteio::*; | |
3 | use crate::frame::*; | |
4 | use std::io::SeekFrom; | |
5 | ||
6 | /// WAVE output writer. | |
7 | pub struct WavWriter<'a> { | |
8 | io: &'a mut ByteWriter<'a>, | |
9 | data_pos: u64, | |
10 | } | |
11 | ||
12 | fn write_byte(wr: &mut ByteWriter, sample: u8) -> ByteIOResult<()> { | |
13 | wr.write_byte(sample) | |
14 | } | |
15 | ||
16 | fn write_s16(wr: &mut ByteWriter, sample: i16) -> ByteIOResult<()> { | |
17 | wr.write_u16le(sample as u16) | |
18 | } | |
19 | ||
20 | fn write_s32(wr: &mut ByteWriter, sample: i32) -> ByteIOResult<()> { | |
21 | wr.write_u16le((sample >> 16) as u16) | |
22 | } | |
23 | ||
24 | fn write_f32(wr: &mut ByteWriter, sample: f32) -> ByteIOResult<()> { | |
25 | let mut out = (sample * 32768.0) as i32; | |
26 | if out < -32768 { out = -32768; } | |
27 | if out > 32767 { out = 32767; } | |
28 | if out < 0 { out += 65536; } | |
29 | wr.write_u16le(out as u16) | |
30 | } | |
31 | ||
32 | macro_rules! write_data { | |
33 | ($wr:expr, $buf:expr, $write:ident) => ({ | |
34 | let len = $buf.get_length(); | |
35 | let ainfo = $buf.get_info(); | |
36 | let nch = ainfo.get_channels() as usize; | |
37 | let mut offs: Vec<usize> = Vec::with_capacity(nch); | |
38 | for ch in 0..nch { offs.push($buf.get_offset(ch)); } | |
39 | let data = $buf.get_data(); | |
40 | ||
41 | for i in 0..len { | |
42 | for ch in 0..nch { | |
43 | let sample = data[offs[ch] + i]; | |
44 | $write($wr, sample)?; | |
45 | } | |
46 | } | |
47 | }) | |
48 | } | |
49 | ||
50 | impl<'a> WavWriter<'a> { | |
51 | /// Constructs a new `WavWriter` instance. | |
52 | pub fn new(io: &'a mut ByteWriter<'a>) -> Self { | |
53 | WavWriter { io, data_pos: 0 } | |
54 | } | |
55 | /// Writes audio format information to the file header. | |
56 | /// | |
57 | /// This function should be called exactly once before writing actual audio data. | |
58 | pub fn write_header(&mut self, ainfo: NAAudioInfo) -> ByteIOResult<()> { | |
59 | let bits = ainfo.get_format().get_bits() as usize; | |
60 | ||
61 | self.io.write_buf(b"RIFF")?; | |
62 | self.io.write_u32le(0)?; | |
63 | self.io.write_buf(b"WAVE")?; | |
64 | ||
65 | self.io.write_buf(b"fmt ")?; | |
66 | self.io.write_u32le(16)?; | |
67 | self.io.write_u16le(0x0001)?; // PCM | |
68 | self.io.write_u16le(u16::from(ainfo.get_channels()))?; | |
69 | self.io.write_u32le(ainfo.get_sample_rate())?; | |
70 | ||
71 | if bits < 16 { | |
72 | self.io.write_u32le(u32::from(ainfo.get_channels()) * ainfo.get_sample_rate())?; | |
73 | self.io.write_u16le(u16::from(ainfo.get_channels()))?; // block align | |
74 | self.io.write_u16le(8)?; | |
75 | } else { | |
76 | self.io.write_u32le(2 * u32::from(ainfo.get_channels()) * ainfo.get_sample_rate())?; | |
77 | self.io.write_u16le(u16::from(2 * ainfo.get_channels()))?; // block align | |
78 | self.io.write_u16le(16)?; | |
79 | } | |
80 | ||
81 | self.io.write_buf(b"data")?; | |
82 | self.io.write_u32le(0)?; | |
83 | ||
84 | self.data_pos = self.io.tell(); | |
85 | Ok(()) | |
86 | } | |
87 | /// Writes audio data. | |
88 | pub fn write_frame(&mut self, abuf: NABufferType) -> ByteIOResult<()> { | |
89 | match abuf { | |
90 | NABufferType::AudioU8(ref buf) => { | |
91 | write_data!(self.io, buf, write_byte); | |
92 | } | |
93 | NABufferType::AudioI16(ref buf) => { | |
94 | write_data!(self.io, buf, write_s16); | |
95 | } | |
96 | NABufferType::AudioI32(ref buf) => { | |
97 | write_data!(self.io, buf, write_s32); | |
98 | } | |
99 | NABufferType::AudioF32(ref buf) => { | |
100 | write_data!(self.io, buf, write_f32); | |
101 | } | |
102 | NABufferType::AudioPacked(ref buf) => { | |
103 | self.io.write_buf(buf.get_data().as_slice())?; | |
104 | } | |
105 | _ => {}, | |
106 | }; | |
107 | Ok(()) | |
108 | } | |
109 | } | |
110 | ||
111 | impl<'a> Drop for WavWriter<'a> { | |
112 | #[allow(unused_variables)] | |
113 | fn drop(&mut self) { | |
114 | let size = self.io.tell(); | |
115 | if (self.data_pos > 0) && (size >= self.data_pos) { | |
116 | let res = self.io.seek(SeekFrom::Start(4)); | |
117 | let res = self.io.write_u32le((size - 8) as u32); | |
118 | let res = self.io.seek(SeekFrom::Start(self.data_pos - 4)); | |
119 | let res = self.io.write_u32le(((size as u64) - self.data_pos) as u32); | |
120 | } | |
121 | } | |
122 | } |