60 lines
2 KiB
Go
60 lines
2 KiB
Go
// Copyright 2024 Martin Riedl
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package gomp4
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import (
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"encoding/binary"
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)
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// TrackExtendsBox Track Extends Box struct
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//
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// 8.8.3 Track Extends Box
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//
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// This sets up default values used by the movie fragments. By setting defaults in this way, space and
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// complexity can be saved in each Track Fragment Box.
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type TrackExtendsBox struct {
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*FullBox
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// identifies the track; this shall be the track ID of a track in the Movie Box
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TrackID uint32
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DefaultSampleDescriptionIndex uint32
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DefaultSampleDuration uint32
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DefaultSampleSize uint32
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DefaultSampleFlags uint32
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}
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const BoxTypeTrackExtends = "trex"
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func init() {
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BoxDefinitions = append(BoxDefinitions, BoxDefinition{
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Type: BoxTypeTrackExtends,
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ParentTypes: []string{BoxTypeMovieExtends},
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Parser: ParseTrackExtendsBox,
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})
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}
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// ParseTrackExtendsBox creates a new track extends box struct based on bytes
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func ParseTrackExtendsBox(parser *Parser, filePosition uint64, headerSize uint32, content []byte) (any, error) {
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box := &TrackExtendsBox{
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FullBox: newFullBox(&Box{filePosition, headerSize}, content[0:4]),
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}
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box.TrackID = binary.BigEndian.Uint32(content[4:8])
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box.DefaultSampleDescriptionIndex = binary.BigEndian.Uint32(content[8:12])
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box.DefaultSampleDuration = binary.BigEndian.Uint32(content[12:16])
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box.DefaultSampleSize = binary.BigEndian.Uint32(content[16:20])
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box.DefaultSampleFlags = binary.BigEndian.Uint32(content[20:24])
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return box, nil
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}
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