feat: new AVC box implementation

AVCVideoStream.go

@@ -0,0 +1,51 @@
+// Copyright 2024 Martin Riedl
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gomp4
+
+type AVCSampleEntry struct {
+	*VisualSampleEntry
+	// TODO: some more
+}
+
+// BoxTypeAVCSampleEntry1 AVC Sample Entry Box
+const BoxTypeAVCSampleEntry1 = "avc1"
+
+// BoxTypeAVCSampleEntry3 AVC Sample Entry Box
+const BoxTypeAVCSampleEntry3 = "avc3"
+
+func init() {
+	BoxDefinitions = append(BoxDefinitions, BoxDefinition{
+		Type:        BoxTypeAVCSampleEntry1,
+		ParentTypes: []string{BoxTypeSampleDescription},
+		Parser:      ParseAVCSampleEntry,
+	}, BoxDefinition{
+		Type:        BoxTypeAVCSampleEntry3,
+		ParentTypes: []string{BoxTypeSampleDescription},
+		Parser:      ParseAVCSampleEntry,
+	})
+}
+
+// ParseAVCSampleEntry creates a new AVC sample entry box struct based on bytes
+func ParseAVCSampleEntry(parser *Parser, filePosition uint64, headerSize uint32, content []byte) (any, error) {
+	sampleEntry, position := ParseVisualSampleEntry(filePosition, headerSize, content)
+	box := &AVCSampleEntry{
+		VisualSampleEntry: sampleEntry,
+	}
+
+	// TODO: parse other fields
+	_ = position
+
+	return box, nil
+}

README.md

@@ -3,7 +3,7 @@
 [![pipeline status](https://gitlab.com/martinr92/gomp4/badges/main/pipeline.svg)](https://gitlab.com/martinr92/gomp4/commits/main)
 [![coverage report](https://gitlab.com/martinr92/gomp4/badges/main/coverage.svg)](https://gitlab.com/martinr92/gomp4/commits/main)
 
-mp4 implementation in golang based on spec ISO ICE 14496-12:2015
+mp4 implementation in golang based on spec ISO/IEC 14496-12:2015
 
 ## Parser
 
@@ -16,7 +16,7 @@ if err := parser.Parse(); err != nil {
 
 ## Progress
 
-Implementation progress of ISO ICE 14496-12:2015:
+Implementation progress of ISO/IEC 14496-12:2015:
 
 | Chapter                                            | Box Types      | Parser |
 |----------------------------------------------------|----------------|-------:|
@@ -118,6 +118,12 @@ Implementation progress of ISO ICE 14496-12:2015:
 | 12.2.7 Audio stream loudness                       | ludt           |      - |
 | 12.4.2 Hint Media Header Box                       | hmhd           |      - |
 
+Implementation progress of ISO/IEC 14496-15:2017:
+
+| Chapter                                            | Box Types                                | Parser |
+|----------------------------------------------------|------------------------------------------|-------:|
+| 5.4.2 AVC video stream definition                  | avc1, avc2, avc3, avc4, avcC, m4ds, btrt |    10% |
+
 ## Helper Tools
 
 - [Online MP4 file parser](https://www.onlinemp4parser.com/)

SampleDescriptionBox.go

@@ -17,7 +17,6 @@ package gomp4
 import (
 	"encoding/binary"
 	"fmt"
-	"log"
 )
 
 // SampleDescriptionBox sample description box struct
@@ -112,17 +111,85 @@ type SampleEntry struct {
 	DataReferenceIndex uint16
 }
 
-func ParseSampleEntry(filePosition uint64, headerSize uint32, content []byte) *SampleEntry {
+func ParseSampleEntry(filePosition uint64, headerSize uint32, content []byte) (*SampleEntry, int) {
 	box := &SampleEntry{
 		Box: &Box{filePosition, headerSize},
 	}
 
 	// skip reserved
-	position := 2 * 8
+	position := 6
 
 	// parse reference index
 	box.DataReferenceIndex = binary.BigEndian.Uint16(content[position : position+2])
-	log.Println("data reference index", box.DataReferenceIndex) // TODO: remove me
+	position += 2
 
-	return box
+	return box, position
+}
+
+// VisualSampleEntry visual sample entry struct
+//
+// 12.1.3 Sample entry
+//
+// Video tracks use VisualSampleEntry.
+//
+// In video tracks, the frame_count field must be 1 unless the specification for the media format explicitly
+// documents this template field and permits larger values. That specification must document both how
+// the individual frames of video are found (their size information) and their timing established. That
+// timing might be as simple as dividing the sample duration by the frame count to establish the frame
+// duration.
+type VisualSampleEntry struct {
+	*SampleEntry
+	Width  uint16
+	Height uint16
+	// give the resolution of the image in pixels‐per‐inch, as a fixed 16.16 number
+	HorizResolution Fixed1616
+	// give the resolution of the image in pixels‐per‐inch, as a fixed 16.16 number
+	VertResolution Fixed1616
+	// indicates how many frames of compressed video are stored in each sample. The
+	// default is 1, for one frame per sample; it may be more than 1 for multiple frames per sample
+	FrameCount uint16
+	// is a name, for informative purposes. It is formatted in a fixed 32‐byte field, with
+	//the first byte set to the number of bytes to be displayed, followed by that number of bytes of
+	//displayable data, and then padding to complete 32 bytes total (including the size byte). The field
+	//may be set to 0.
+	CompressorName string
+	Depth          uint16
+}
+
+func ParseVisualSampleEntry(filePosition uint64, headerSize uint32, content []byte) (*VisualSampleEntry, int) {
+	sampleEntry, position := ParseSampleEntry(filePosition, headerSize, content)
+	box := &VisualSampleEntry{
+		SampleEntry: sampleEntry,
+	}
+
+	// skip pre-defined and reserved bytes
+	position += 2 + 2 + 4*3
+
+	// parse resolution
+	box.Width = binary.BigEndian.Uint16(content[position : position+2])
+	box.Height = binary.BigEndian.Uint16(content[position+2 : position+4])
+	box.HorizResolution = NewFixed1616ByBytes(content[position+4 : position+8])
+	box.VertResolution = NewFixed1616ByBytes(content[position+8 : position+12])
+	position += 12
+
+	// skip reserved bytes
+	position += 4
+
+	// parse frame count
+	box.FrameCount = binary.BigEndian.Uint16(content[position : position+2])
+	position += 2
+
+	// parse compressor name length (32bytes total)
+	compressorNameLength := int(content[position])
+	box.CompressorName = string(content[position+1 : position+1+compressorNameLength])
+	position += 32
+
+	// parse depth
+	box.Depth = binary.BigEndian.Uint16(content[position : position+2])
+	position += 2
+
+	// skip pre-defined bytes
+	position += 2
+
+	return box, position
 }