mse_fmp4 0.2.0

A library for generating fragmented MP4 that playable via Media Source Extensions
Documentation 
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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207

//! AAC related constituent elements.
use crate::{ErrorKind, Result};
use byteorder::{BigEndian, ReadBytesExt};
use std::io::Read;

pub(crate) const SAMPLES_IN_FRAME: usize = 1024;

#[derive(Debug, Clone)]
pub(crate) struct AdtsHeader {
    pub profile: AacProfile,
    pub sampling_frequency: SamplingFrequency,
    pub private: bool,
    pub channel_configuration: ChannelConfiguration,
    pub frame_len: u16,       // u13
    pub buffer_fullness: u16, // u11
}
impl AdtsHeader {
    const SYNC_WORD: u16 = 0b1111_1111_1111;
    const MPEG_VERSION_4: u8 = 0;
    const HEADER_LEN_WITHOUT_CRC: u16 = 7;

    pub fn raw_data_blocks_len(&self) -> u16 {
        self.frame_len - Self::HEADER_LEN_WITHOUT_CRC
    }

    pub fn read_from<R: Read>(mut reader: R) -> Result<Self> {
        let n = track_io!(reader.read_u16::<BigEndian>())?;
        track_assert_eq!(n >> 4, Self::SYNC_WORD, ErrorKind::InvalidInput);

        let mpeg_version = ((n >> 3) & 0b1) as u8;
        let layer = (n >> 1) & 0b11;
        let crc_protection_absent = (n & 0b1) != 0;
        track_assert_eq!(mpeg_version, Self::MPEG_VERSION_4, ErrorKind::Unsupported);
        track_assert_eq!(layer, 0, ErrorKind::InvalidInput);

        let n = track_io!(reader.read_u8())?;
        let profile = match n >> 6 {
            0 => AacProfile::Main,
            1 => AacProfile::Lc,
            2 => AacProfile::Ssr,
            3 => AacProfile::Ltp,
            _ => unreachable!(),
        };
        let sampling_frequency = track!(SamplingFrequency::from_index((n >> 2) & 0b1111))?;
        let private = (n & 0b10) != 0;
        let channel_msb = n & 0b1;

        let n = track_io!(reader.read_u8())?;
        let channel_configuration =
            track!(ChannelConfiguration::from_u8((channel_msb << 2) | (n >> 6)))?;
        let originality = (n & 0b10_0000) != 0;
        let home = (n & 0b01_0000) != 0;
        let copyrighted = (n & 0b00_1000) != 0;
        let copyright_id_start = (n & 0b00_0100) != 0;
        track_assert!(!originality, ErrorKind::Unsupported);
        track_assert!(!home, ErrorKind::Unsupported);
        track_assert!(!copyrighted, ErrorKind::Unsupported);
        track_assert!(!copyright_id_start, ErrorKind::Unsupported);
        let frame_len_msb_2bits = u16::from(n & 0b11);

        let n = track_io!(reader.read_u16::<BigEndian>())?;
        let frame_len = (frame_len_msb_2bits << 11) | (n >> 5);
        let buffer_fullness_msb_5bits = n & 0b1_1111;

        let n = track_io!(reader.read_u8())?;
        let buffer_fullness = (buffer_fullness_msb_5bits << 5) | u16::from(n >> 2);
        let raw_data_blocks_minus_1 = n & 0b11;
        track_assert_eq!(raw_data_blocks_minus_1, 0, ErrorKind::Unsupported);
        if !crc_protection_absent {
            // 16bits
            track_panic!(ErrorKind::Unsupported);
        }

        Ok(AdtsHeader {
            profile,
            sampling_frequency,
            private,
            channel_configuration,
            frame_len,
            buffer_fullness,
        })
    }
}

/// Profile.
#[allow(missing_docs)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum AacProfile {
    /// AAC Main.
    Main = 0,

    /// AAC LC (Low Complexity).
    Lc = 1,

    /// AAC SSR (Scalable Sample Rate).
    Ssr = 2,

    /// AAC LTP (Long Term Prediction).
    Ltp = 3,
}

/// Sampling frequency.
#[allow(missing_docs)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum SamplingFrequency {
    Hz96000 = 0,
    Hz88200 = 1,
    Hz64000 = 2,
    Hz48000 = 3,
    Hz44100 = 4,
    Hz32000 = 5,
    Hz24000 = 6,
    Hz22050 = 7,
    Hz16000 = 8,
    Hz12000 = 9,
    Hz11025 = 10,
    Hz8000 = 11,
    Hz7350 = 12,
}
impl SamplingFrequency {
    pub(crate) fn as_u32(&self) -> u32 {
        match *self {
            SamplingFrequency::Hz96000 => 96_000,
            SamplingFrequency::Hz88200 => 88_200,
            SamplingFrequency::Hz64000 => 64_000,
            SamplingFrequency::Hz48000 => 48_000,
            SamplingFrequency::Hz44100 => 44_100,
            SamplingFrequency::Hz32000 => 32_000,
            SamplingFrequency::Hz24000 => 24_000,
            SamplingFrequency::Hz22050 => 22_050,
            SamplingFrequency::Hz16000 => 16_000,
            SamplingFrequency::Hz12000 => 12_000,
            SamplingFrequency::Hz11025 => 11_025,
            SamplingFrequency::Hz8000 => 8_000,
            SamplingFrequency::Hz7350 => 7_350,
        }
    }

    pub(crate) fn as_index(&self) -> u8 {
        *self as u8
    }

    fn from_index(n: u8) -> Result<Self> {
        Ok(match n {
            0 => SamplingFrequency::Hz96000,
            1 => SamplingFrequency::Hz88200,
            2 => SamplingFrequency::Hz64000,
            3 => SamplingFrequency::Hz48000,
            4 => SamplingFrequency::Hz44100,
            5 => SamplingFrequency::Hz32000,
            6 => SamplingFrequency::Hz24000,
            7 => SamplingFrequency::Hz22050,
            8 => SamplingFrequency::Hz16000,
            9 => SamplingFrequency::Hz12000,
            10 => SamplingFrequency::Hz11025,
            11 => SamplingFrequency::Hz8000,
            12 => SamplingFrequency::Hz7350,
            13 | 14 => track_panic!(ErrorKind::InvalidInput, "Reserved"),
            15 => track_panic!(ErrorKind::InvalidInput, "Forbidden"),
            _ => track_panic!(ErrorKind::InvalidInput, "Unreachable"),
        })
    }
}

/// Channel configuration.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum ChannelConfiguration {
    /// Channel configuration is sent via an inband PCE.
    SentViaInbandPce = 0,

    /// 1 channel: front-center.
    OneChannel = 1,

    /// 2 channels: front-left, front-right.
    TwoChannels = 2,

    /// 3 channels: front-center, front-left, front-right.
    ThreeChannels = 3,

    /// 4 channels: front-center, front-left, front-right, back-center.
    FourChannels = 4,

    /// 5 channels: front-center, front-left, front-right, back-left, back-right.
    FiveChannels = 5,

    /// 6 channels: front-center, front-left, front-right, back-left, back-right, LFE-channel.
    SixChannels = 6,

    /// 8 channels: front-center, front-left, front-right, side-left, side-right, back-left,
    /// back-right, LFE-channel.
    EightChannels = 7,
}
impl ChannelConfiguration {
    fn from_u8(n: u8) -> Result<Self> {
        Ok(match n {
            0 => ChannelConfiguration::SentViaInbandPce,
            1 => ChannelConfiguration::OneChannel,
            2 => ChannelConfiguration::TwoChannels,
            3 => ChannelConfiguration::ThreeChannels,
            4 => ChannelConfiguration::FourChannels,
            5 => ChannelConfiguration::FiveChannels,
            6 => ChannelConfiguration::SixChannels,
            7 => ChannelConfiguration::EightChannels,
            _ => track_panic!(ErrorKind::InvalidInput, "Unreachable"),
        })
    }
}