mp4/mp4box/
mdhd.rs

1use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
2use serde::Serialize;
3use std::char::{decode_utf16, REPLACEMENT_CHARACTER};
4use std::io::{Read, Seek, Write};
5
6use crate::mp4box::*;
7
8#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
9pub struct MdhdBox {
10    pub version: u8,
11    pub flags: u32,
12    pub creation_time: u64,
13    pub modification_time: u64,
14    pub timescale: u32,
15    pub duration: u64,
16    pub language: String,
17}
18
19impl MdhdBox {
20    pub fn get_type(&self) -> BoxType {
21        BoxType::MdhdBox
22    }
23
24    pub fn get_size(&self) -> u64 {
25        let mut size = HEADER_SIZE + HEADER_EXT_SIZE;
26
27        if self.version == 1 {
28            size += 28;
29        } else if self.version == 0 {
30            size += 16;
31        }
32        size += 4;
33        size
34    }
35}
36
37impl Default for MdhdBox {
38    fn default() -> Self {
39        MdhdBox {
40            version: 0,
41            flags: 0,
42            creation_time: 0,
43            modification_time: 0,
44            timescale: 1000,
45            duration: 0,
46            language: String::from("und"),
47        }
48    }
49}
50
51impl Mp4Box for MdhdBox {
52    fn box_type(&self) -> BoxType {
53        self.get_type()
54    }
55
56    fn box_size(&self) -> u64 {
57        self.get_size()
58    }
59
60    fn to_json(&self) -> Result<String> {
61        Ok(serde_json::to_string(&self).unwrap())
62    }
63
64    fn summary(&self) -> Result<String> {
65        let s = format!(
66            "creation_time={} timescale={} duration={} language={}",
67            self.creation_time, self.timescale, self.duration, self.language
68        );
69        Ok(s)
70    }
71}
72
73impl<R: Read + Seek> ReadBox<&mut R> for MdhdBox {
74    fn read_box(reader: &mut R, size: u64) -> Result<Self> {
75        let start = box_start(reader)?;
76
77        let (version, flags) = read_box_header_ext(reader)?;
78
79        let (creation_time, modification_time, timescale, duration) = if version == 1 {
80            (
81                reader.read_u64::<BigEndian>()?,
82                reader.read_u64::<BigEndian>()?,
83                reader.read_u32::<BigEndian>()?,
84                reader.read_u64::<BigEndian>()?,
85            )
86        } else if version == 0 {
87            (
88                reader.read_u32::<BigEndian>()? as u64,
89                reader.read_u32::<BigEndian>()? as u64,
90                reader.read_u32::<BigEndian>()?,
91                reader.read_u32::<BigEndian>()? as u64,
92            )
93        } else {
94            return Err(Error::InvalidData("version must be 0 or 1"));
95        };
96        let language_code = reader.read_u16::<BigEndian>()?;
97        let language = language_string(language_code);
98
99        skip_bytes_to(reader, start + size)?;
100
101        Ok(MdhdBox {
102            version,
103            flags,
104            creation_time,
105            modification_time,
106            timescale,
107            duration,
108            language,
109        })
110    }
111}
112
113impl<W: Write> WriteBox<&mut W> for MdhdBox {
114    fn write_box(&self, writer: &mut W) -> Result<u64> {
115        let size = self.box_size();
116        BoxHeader::new(self.box_type(), size).write(writer)?;
117
118        write_box_header_ext(writer, self.version, self.flags)?;
119
120        if self.version == 1 {
121            writer.write_u64::<BigEndian>(self.creation_time)?;
122            writer.write_u64::<BigEndian>(self.modification_time)?;
123            writer.write_u32::<BigEndian>(self.timescale)?;
124            writer.write_u64::<BigEndian>(self.duration)?;
125        } else if self.version == 0 {
126            writer.write_u32::<BigEndian>(self.creation_time as u32)?;
127            writer.write_u32::<BigEndian>(self.modification_time as u32)?;
128            writer.write_u32::<BigEndian>(self.timescale)?;
129            writer.write_u32::<BigEndian>(self.duration as u32)?;
130        } else {
131            return Err(Error::InvalidData("version must be 0 or 1"));
132        }
133
134        let language_code = language_code(&self.language);
135        writer.write_u16::<BigEndian>(language_code)?;
136        writer.write_u16::<BigEndian>(0)?; // pre-defined
137
138        Ok(size)
139    }
140}
141
142fn language_string(language: u16) -> String {
143    let mut lang: [u16; 3] = [0; 3];
144
145    lang[0] = ((language >> 10) & 0x1F) + 0x60;
146    lang[1] = ((language >> 5) & 0x1F) + 0x60;
147    lang[2] = ((language) & 0x1F) + 0x60;
148
149    // Decode utf-16 encoded bytes into a string.
150    let lang_str = decode_utf16(lang.iter().cloned())
151        .map(|r| r.unwrap_or(REPLACEMENT_CHARACTER))
152        .collect::<String>();
153
154    lang_str
155}
156
157fn language_code(language: &str) -> u16 {
158    let mut lang = language.encode_utf16();
159    let mut code = (lang.next().unwrap_or(0) & 0x1F) << 10;
160    code += (lang.next().unwrap_or(0) & 0x1F) << 5;
161    code += lang.next().unwrap_or(0) & 0x1F;
162    code
163}
164
165#[cfg(test)]
166mod tests {
167    use super::*;
168    use crate::mp4box::BoxHeader;
169    use std::io::Cursor;
170
171    fn test_language_code(lang: &str) {
172        let code = language_code(lang);
173        let lang2 = language_string(code);
174        assert_eq!(lang, lang2);
175    }
176
177    #[test]
178    fn test_language_codes() {
179        test_language_code("und");
180        test_language_code("eng");
181        test_language_code("kor");
182    }
183
184    #[test]
185    fn test_mdhd32() {
186        let src_box = MdhdBox {
187            version: 0,
188            flags: 0,
189            creation_time: 100,
190            modification_time: 200,
191            timescale: 48000,
192            duration: 30439936,
193            language: String::from("und"),
194        };
195        let mut buf = Vec::new();
196        src_box.write_box(&mut buf).unwrap();
197        assert_eq!(buf.len(), src_box.box_size() as usize);
198
199        let mut reader = Cursor::new(&buf);
200        let header = BoxHeader::read(&mut reader).unwrap();
201        assert_eq!(header.name, BoxType::MdhdBox);
202        assert_eq!(src_box.box_size(), header.size);
203
204        let dst_box = MdhdBox::read_box(&mut reader, header.size).unwrap();
205        assert_eq!(src_box, dst_box);
206    }
207
208    #[test]
209    fn test_mdhd64() {
210        let src_box = MdhdBox {
211            version: 0,
212            flags: 0,
213            creation_time: 100,
214            modification_time: 200,
215            timescale: 48000,
216            duration: 30439936,
217            language: String::from("eng"),
218        };
219        let mut buf = Vec::new();
220        src_box.write_box(&mut buf).unwrap();
221        assert_eq!(buf.len(), src_box.box_size() as usize);
222
223        let mut reader = Cursor::new(&buf);
224        let header = BoxHeader::read(&mut reader).unwrap();
225        assert_eq!(header.name, BoxType::MdhdBox);
226        assert_eq!(src_box.box_size(), header.size);
227
228        let dst_box = MdhdBox::read_box(&mut reader, header.size).unwrap();
229        assert_eq!(src_box, dst_box);
230    }
231}