71 lines
2.6 KiB
Go
71 lines
2.6 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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// HandlerReferenceBox handler reference box struct
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//
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// 8.4.3 Handler Reference Box
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//
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// Box Type: ‘hdlr’
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// Container: Media Box (‘mdia’) or Meta Box (‘meta’)
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// Mandatory: Yes
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// Quantity: Exactly one
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//
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// This box within a Media Box declares media type of the track, and thus the process by which the mediadata
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// in the track is presented. For example, a format for which the decoder delivers video would be
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// stored in a video track, identified by being handled by a video handler. The documentation of the
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// storage of a media format identifies the media type which that format uses.
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//
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// This box when present within a Meta Box, declares the structure or format of the 'meta' box contents.
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// There is a general handler for metadata streams of any type; the specific format is identified by the
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// sample entry, as for video or audio, for example.
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type HandlerReferenceBox struct {
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*FullBox
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// – when present in a media box, contains a value as defined in clause 12, or a value from a derived
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// specification, or registration.
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// - when present in a meta box, contains an appropriate value to indicate the format of the meta
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// box contents. The value ‘null’ can be used in the primary meta box to indicate that it is
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// merely being used to hold resources.
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HandlerType uint32
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// is a null‐terminated string in UTF‐8 characters which gives a human‐readable name for the
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// track type (for debugging and inspection purposes).
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Name string
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}
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func ParseHandlerReferenceBox(filePosition uint64, headerSize uint32, content []byte) *HandlerReferenceBox {
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box := &HandlerReferenceBox{
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FullBox: newFullBox(&Box{filePosition, headerSize}, content[0:4]),
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}
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// box content + 32bit pre-defined
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position := 4 + 4
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// parse handler type
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box.HandlerType = binary.BigEndian.Uint32(content[position : position+4])
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position += 4
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// 3x32bit reserved
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position += 3 * 4
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// parse name
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box.Name, _ = ParseStringNullTerminated(content[position:])
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return box
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}
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