michael.heier/jellyfin
1
0
Fork 0
Code Issues Pull Requests Actions 2 Packages Projects Releases Wiki Activity

Fix the DecodeJfif function to get image sizes

Browse Source 
Added support for progressive DCT-based JPEGs.
By adding a check for the SOF2 marker (C2)
This commit is contained in:
Bond_009 2019-01-08 22:10:11 +01:00
parent c5c44744fc
commit 432be01934
1 changed files with 18 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
Emby.Drawing/Common/ImageHeader.cs
View File

@ -121,7 +121,7 @@ namespace Emby.Drawing.Common
/// </summary>
/// <param name="binaryReader">The binary reader.</param>
/// <returns>System.Int16.</returns>
private static short ReadLittleEndianInt16(BinaryReader binaryReader)
private static short ReadLittleEndianInt16(this BinaryReader binaryReader)
{
var bytes = new byte[sizeof(short)];
@ -137,7 +137,7 @@ namespace Emby.Drawing.Common
/// </summary>
/// <param name="binaryReader">The binary reader.</param>
/// <returns>System.Int32.</returns>
private static int ReadLittleEndianInt32(BinaryReader binaryReader)
private static int ReadLittleEndianInt32(this BinaryReader binaryReader)
{
var bytes = new byte[sizeof(int)];
for (int i = 0; i < sizeof(int); i += 1)
@ -205,25 +205,30 @@ namespace Emby.Drawing.Common
/// <exception cref="System.ArgumentException"></exception>
private static ImageSize DecodeJfif(BinaryReader binaryReader)
{
// A JPEG image consists of a sequence of segments,
// each beginning with a marker, each of which begins with a 0xFF byte
// followed by a byte indicating what kind of marker it is.
// Source: https://en.wikipedia.org/wiki/JPEG#Syntax_and_structure
while (binaryReader.ReadByte() == 0xff)
{
byte marker = binaryReader.ReadByte();
short chunkLength = ReadLittleEndianInt16(binaryReader);
if (marker == 0xc0)
short chunkLength = binaryReader.ReadLittleEndianInt16();
// SOF0: Indicates that this is a baseline DCT-based JPEG,
// and specifies the width, height, number of components, and component subsampling
// SOF2: Indicates that this is a progressive DCT-based JPEG,
// and specifies the width, height, number of components, and component subsampling
if (marker == 0xc0 || marker == 0xc2)
{
binaryReader.ReadByte();
int height = ReadLittleEndianInt16(binaryReader);
int width = ReadLittleEndianInt16(binaryReader);
return new ImageSize
{
Width = width,
Height = height
};
// https://help.accusoft.com/ImageGear/v18.2/Windows/ActiveX/IGAX-10-12.html
binaryReader.ReadByte(); // We don't care about the first byte
int height = binaryReader.ReadLittleEndianInt16();
int width = binaryReader.ReadLittleEndianInt16();
return new ImageSize(width, height);
}
if (chunkLength < 0)
{
var uchunkLength = (ushort)chunkLength;
ushort uchunkLength = (ushort)chunkLength;
binaryReader.ReadBytes(uchunkLength - 2);
}
else