HaishinKit.swift/Sources/MP4/MP4SampleToChunkBox.swift

70 lines
2.2 KiB
Swift

import Foundation
/// ISO/IEC 14496-12 5th 8.7.4.2
struct MP4SampleToChunkBox: MP4FullBox {
struct Entry: Equatable, CustomDebugStringConvertible {
let firstChunk: UInt32
let samplesPerChunk: UInt32
let sampleDescriptionIndex: UInt32
var debugDescription: String {
Mirror(reflecting: self).debugDescription
}
}
// MARK: MP4FullBox
var size: UInt32 = 0
let type: String = "stsc"
var offset: UInt64 = 0
var children: [MP4BoxConvertible] = []
var version: UInt8 = 0
var flags: UInt32 = 0
// MARK: MP4SampleToChunkBox
var entries: [Entry] = []
}
extension MP4SampleToChunkBox: DataConvertible {
var data: Data {
get {
let buffer = ByteArray()
.writeUInt32(size)
.writeUTF8Bytes(type)
.writeUInt8(version)
.writeUInt24(flags)
.writeUInt32(UInt32(entries.count))
for entry in entries {
buffer
.writeUInt32(entry.firstChunk)
.writeUInt32(entry.samplesPerChunk)
.writeUInt32(entry.sampleDescriptionIndex)
}
let size = buffer.position
buffer.position = 0
buffer.writeUInt32(UInt32(size))
return buffer.data
}
set {
do {
let buffer = ByteArray(data: newValue)
size = try buffer.readUInt32()
_ = try buffer.readUTF8Bytes(4)
buffer.position += 4
let numberOfEntries: UInt32 = try buffer.readUInt32()
entries.removeAll()
for _ in 0..<numberOfEntries {
entries.append(Entry(
firstChunk: try buffer.readUInt32(),
samplesPerChunk: try buffer.readUInt32(),
sampleDescriptionIndex: try buffer.readUInt32()
))
}
} catch {
logger.error(error)
}
}
}
}
extension MP4Box.Names {
static let stsc = MP4Box.Name<MP4SampleToChunkBox>(rawValue: "stsc")
}