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Implement MP4 transformation matrixes with support for basic rotations

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This commit is contained in:
Thulinma 2022-11-24 03:15:45 +01:00
parent 1aaaeebb24
commit e69050224b
2 changed files with 62 additions and 14 deletions
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70
lib/mp4_generic.cpp
View file

@ -1604,9 +1604,10 @@ namespace MP4{
setDuration(duration); // in ms
setRate(0x00010000); // playback rate 1.0X
setVolume(0x0100); // volume 1.0X
setMatrix(0x00010000, 0);
setMatrix(0x00010000, 4);
setMatrix(0x40000000, 8);
//Identity Transformation Matrix
setMatrix(1, 0);
setMatrix(1, 4);
setMatrix(1, 8);
setTrackID(0xFFFFFFFF); // empty track numbers is unknown
}
@ -1708,24 +1709,45 @@ namespace MP4{
// 10 bytes reserved in between
uint32_t MVHD::getMatrixCount(){return 9;}
void MVHD::setMatrix(int32_t newMatrix, size_t index){
void MVHD::setMatrix(double newMatrix, size_t index){
int offset = 0;
if (getVersion() == 0){
offset = 24 + 2 + 10;
}else{
offset = 36 + 2 + 10;
}
setInt32(newMatrix, offset + index * 4);
//Indexes 2, 6 and 8 are 2.30 fixed point, the rest is 16.16 fixed point.
if (index == 2 || index == 5 || index == 8){
setInt32((int32_t)(newMatrix * 1073741824.0), offset + index * 4);
}else{
setInt32((int32_t)(newMatrix * 65536.0), offset + index * 4);
}
}
int32_t MVHD::getMatrix(size_t index){
double MVHD::getMatrix(size_t index){
int offset = 0;
if (getVersion() == 0){
offset = 36;
}else{
offset = 48;
}
return getInt32(offset + index * 4);
//Indexes 2, 6 and 8 are 2.30 fixed point, the rest is 16.16 fixed point.
if (index == 2 || index == 5 || index == 8){
return (int32_t)getInt32(offset + index * 4) / 1073741824.0;
}else{
return (int32_t)getInt32(offset + index * 4) / 65536.0;
}
}
uint16_t MVHD::getRotation(){
//These are oversimplifications that ignore scaling and translation
//We also only handle the 90-degree-increment rotations, nothing else
//That should cover practically all videos we'll encounter though...
if (getMatrix(1) > 0.0 && getMatrix(3) < 0.0){return 90;}
if (getMatrix(1) < 0.0 && getMatrix(3) > 0.0){return 270;}
if (getMatrix(0) > 0.0 && getMatrix(4) > 0.0){return 0;}
if (getMatrix(0) < 0.0 && getMatrix(4) < 0.0){return 180;}
return 0; //Unknown rotation, assume none
}
// 24 bytes of pre-defined in between
@ -1761,6 +1783,7 @@ namespace MP4{
if (i != getMatrixCount() - 1){r << ", ";}
}
r << std::endl;
r << std::string(indent + 1, ' ') << "Rotation (calculated from Matrix): " << getRotation() << std::endl;
r << std::string(indent + 1, ' ') << "next_track_ID: " << getTrackID() << std::endl;
return r.str();
}
@ -1937,9 +1960,10 @@ namespace MP4{
}
memset(data + payloadOffset, 0, 84); // set all bytes (92 - 8) to zeroes
setFlags(3); // ENABLED | IN_MOVIE
setMatrix(0x00010000, 0);
setMatrix(0x00010000, 4);
setMatrix(0x40000000, 8);
//Identity transformation Matrix
setMatrix(1, 0);
setMatrix(1, 4);
setMatrix(1, 8);
setVolume(0x0100);
}
@ -2064,7 +2088,12 @@ namespace MP4{
}else{
offset = 52;
}
setInt32(newMatrix, offset + index * 4);
//Indexes 2, 6 and 8 are 2.30 fixed point, the rest is 16.16 fixed point.
if (index == 2 || index == 5 || index == 8){
setInt32((int32_t)(newMatrix * 1073741824.0), offset + index * 4);
}else{
setInt32((int32_t)(newMatrix * 65536.0), offset + index * 4);
}
}
int32_t TKHD::getMatrix(size_t index){
@ -2074,7 +2103,23 @@ namespace MP4{
}else{
offset = 52;
}
return getInt32(offset + index * 4);
//Indexes 2, 6 and 8 are 2.30 fixed point, the rest is 16.16 fixed point.
if (index == 2 || index == 5 || index == 8){
return (int32_t)getInt32(offset + index * 4) / 1073741824.0;
}else{
return (int32_t)getInt32(offset + index * 4) / 65536.0;
}
}
uint16_t TKHD::getRotation(){
//These are oversimplifications that ignore scaling and translation
//We also only handle the 90-degree-increment rotations, nothing else
//That should cover practically all videos we'll encounter though...
if (getMatrix(1) > 0.0 && getMatrix(3) < 0.0){return 90;}
if (getMatrix(1) < 0.0 && getMatrix(3) > 0.0){return 270;}
if (getMatrix(0) > 0.0 && getMatrix(4) > 0.0){return 0;}
if (getMatrix(0) < 0.0 && getMatrix(4) < 0.0){return 180;}
return 0; //Unknown rotation, assume none
}
void TKHD::setWidth(double newWidth){
@ -2126,6 +2171,7 @@ namespace MP4{
if (i != getMatrixCount() - 1){r << ", ";}
}
r << std::endl;
r << std::string(indent + 1, ' ') << "Rotation (calculated from Matrix): " << getRotation() << std::endl;
r << std::string(indent + 1, ' ') << "Width: " << getWidth() << std::endl;
r << std::string(indent + 1, ' ') << "Height: " << getHeight() << std::endl;
return r.str();

6
lib/mp4_generic.h
View file

@ -470,8 +470,9 @@ namespace MP4{
void setVolume(uint16_t newVolume);
uint16_t getVolume();
uint32_t getMatrixCount();
void setMatrix(int32_t newMatrix, size_t index);
int32_t getMatrix(size_t index);
void setMatrix(double newMatrix, size_t index);
double getMatrix(size_t index);
uint16_t getRotation();
void setTrackID(uint32_t newTrackID);
uint32_t getTrackID();
std::string toPrettyString(uint32_t indent = 0);
@ -529,6 +530,7 @@ namespace MP4{
uint32_t getMatrixCount();
void setMatrix(int32_t newMatrix, size_t index);
int32_t getMatrix(size_t index);
uint16_t getRotation();
void setWidth(double newWidth);
double getWidth();