From f7187d49903580af1bae4505a46453602c6f7e84 Mon Sep 17 00:00:00 2001
From: Ethan Dye <mrtops03@gmail.com>
Date: Mon, 30 Sep 2024 09:37:42 -0600
Subject: [PATCH] Fix decoding of even lines

Signed-off-by: Ethan Dye <mrtops03@gmail.com>
---
 .../Subtitles/PGS/Parsers/RLE/RLEData.swift   | 40 ++++++++++++++++---
 .../Subtitles/VobSub/VobSubParser.swift       |  5 ++-
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/Sources/macSubtitleOCR/Subtitles/PGS/Parsers/RLE/RLEData.swift b/Sources/macSubtitleOCR/Subtitles/PGS/Parsers/RLE/RLEData.swift
index 1d17f64..52602eb 100644
--- a/Sources/macSubtitleOCR/Subtitles/PGS/Parsers/RLE/RLEData.swift
+++ b/Sources/macSubtitleOCR/Subtitles/PGS/Parsers/RLE/RLEData.swift
@@ -87,6 +87,7 @@ class RLEData {
         var i = 0
         var y = 0
         var x = 0
+        var onlyHalf = false
         var currentNibbles: [UInt8?] = [nibbles[i], nibbles[i + 1]]
         i += 2
         while currentNibbles[1] != nil, y < height {
@@ -103,11 +104,33 @@ class RLEData {
             }
             let color = UInt8(nibble & 0x03)
             var run = Int(nibble >> 2)
-            if (image.count % width) == 0, color != 0 {
-                if run == 15 {
+
+            if onlyHalf, color != 0 {
+                print("Got something weird, fixing it \(color) \(run)")
+                if 1 <= run, run <= 3 {
                     i -= 4
+                    currentNibbles = [nibbles[i], nibbles[i + 1]]
+                    i += 2
                     continue
-                }
+                } else if 4 <= run, run <= 15  {
+                    i -= 5
+                    currentNibbles = [nibbles[i], nibbles[i + 1]]
+                    i += 2
+                    continue
+                }// else if 16 <= run, run <= 63 {
+                //     i -= 7
+                //     currentNibbles = [nibbles[i], nibbles[i + 1]]
+                //     i += 2
+                //     continue
+                // } //else if 64 <= run, run <= 255 {
+                //     i -= 8
+                //     currentNibbles = [nibbles[i], nibbles[i + 1]]
+                //     i += 2
+                //     continue
+                // }
+            }
+            if onlyHalf {
+                onlyHalf = false
             }
 
             x += Int(run)
@@ -115,16 +138,21 @@ class RLEData {
             if run == 0 || x >= width {
                 run += width - x
                 x = 0
-                if y % 2 == 0 {
-                    odd.toggle()
-                }
+                // Index is byte aligned at start of new line
+                // if y % 2 == 0, y > height / 2 {
+                //     odd.toggle()
+                // }
                 y += 1
+                onlyHalf = true
                 image.append(contentsOf: repeatElement(color, count: run))
                 image.append(contentsOf: repeatElement(0, count: width))
                 continue
             }
 
             image.append(contentsOf: repeatElement(color, count: run))
+            if image.count == 181585 {
+                print("Image count is 181585")
+            }
         }
         return image
     }
diff --git a/Sources/macSubtitleOCR/Subtitles/VobSub/VobSubParser.swift b/Sources/macSubtitleOCR/Subtitles/VobSub/VobSubParser.swift
index 8652e7b..9c70344 100644
--- a/Sources/macSubtitleOCR/Subtitles/VobSub/VobSubParser.swift
+++ b/Sources/macSubtitleOCR/Subtitles/VobSub/VobSubParser.swift
@@ -22,7 +22,8 @@ func readSubFrame(pic: inout Subtitle, subFile: FileHandle, offset: UInt64, next
     var rleLengthFound = 0
     pic.numberOfColors = 16
 
-    logger.info("Reading subtitle frame at offset \(offset) with next offset \(nextOffset)")
+    // logger.info("Reading subtitle frame at offset \(offset) with next offset \(nextOffset)")
+    print("Reading subtitle frame at offset \(offset) with next offset \(nextOffset)")
     subFile.seek(toFileOffset: offset)
     repeat {
         let startOffset = subFile.offsetInFile
@@ -224,6 +225,8 @@ func decodeImage(subtitle: Subtitle, fileBuffer _: FileHandle) throws -> Data {
     let rleData = RLEData(data: subtitle.imageData, width: width, height: height)
     bitmap = try rleData.decodeVobSub()
 
+    // Investigate what role the length of the data plays
+
     // decode even lines
     // decodeLine(subtitle.imageData, rleOffset: subtitle.imageEvenOffset, rleLength: sizeEven, target: &bitmap, targetOffset: 0, width: width, maxPixels: width * (height / 2 + (height & 1)))