From 8b408dbf0ff556b6ed40c496ef3ea3821bb339ac Mon Sep 17 00:00:00 2001
From: Roberto Togni <r_togni@tiscali.it>
Date: Mon, 31 May 2004 20:18:08 +0000
Subject: Add support for qtrle4 (16 colors/gray levels)

Originally committed as revision 3183 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/qtrle.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

(limited to 'libavcodec/qtrle.c')

diff --git a/libavcodec/qtrle.c b/libavcodec/qtrle.c
index 55fa98663d..1fedaccf16 100644
--- a/libavcodec/qtrle.c
+++ b/libavcodec/qtrle.c
@@ -74,6 +74,92 @@ static void qtrle_decode_2bpp(QtrleContext *s)
 
 static void qtrle_decode_4bpp(QtrleContext *s)
 {
+    int stream_ptr;
+    int header;
+    int start_line;
+    int lines_to_change;
+    int rle_code;
+    int row_ptr, pixel_ptr;
+    int row_inc = s->frame.linesize[0];
+    unsigned char pi1, pi2, pi3, pi4, pi5, pi6, pi7, pi8;  /* 8 palette indices */
+    unsigned char *rgb = s->frame.data[0];
+    int pixel_limit = s->frame.linesize[0] * s->avctx->height;
+
+    /* check if this frame is even supposed to change */
+    if (s->size < 8)
+        return;
+
+    /* start after the chunk size */
+    stream_ptr = 4;
+
+    /* fetch the header */
+    CHECK_STREAM_PTR(2);
+    header = BE_16(&s->buf[stream_ptr]);
+    stream_ptr += 2;
+
+    /* if a header is present, fetch additional decoding parameters */
+    if (header & 0x0008) {
+        CHECK_STREAM_PTR(8);
+        start_line = BE_16(&s->buf[stream_ptr]);
+        stream_ptr += 4;
+        lines_to_change = BE_16(&s->buf[stream_ptr]);
+        stream_ptr += 4;
+    } else {
+        start_line = 0;
+        lines_to_change = s->avctx->height;
+    }
+
+    row_ptr = row_inc * start_line;
+    while (lines_to_change--) {
+        CHECK_STREAM_PTR(2);
+        pixel_ptr = row_ptr + (8 * (s->buf[stream_ptr++] - 1));
+
+        while ((rle_code = (signed char)s->buf[stream_ptr++]) != -1) {
+            if (rle_code == 0) {
+                /* there's another skip code in the stream */
+                CHECK_STREAM_PTR(1);
+                pixel_ptr += (8 * (s->buf[stream_ptr++] - 1));
+            } else if (rle_code < 0) {
+                /* decode the run length code */
+                rle_code = -rle_code;
+                /* get the next 4 bytes from the stream, treat them as palette
+                 * indices, and output them rle_code times */
+                CHECK_STREAM_PTR(4);
+                pi1 = ((s->buf[stream_ptr]) >> 4) & 0x0f;
+                pi2 = (s->buf[stream_ptr++]) & 0x0f;
+                pi3 = ((s->buf[stream_ptr]) >> 4) & 0x0f;
+                pi4 = (s->buf[stream_ptr++]) & 0x0f;
+                pi5 = ((s->buf[stream_ptr]) >> 4) & 0x0f;
+                pi6 = (s->buf[stream_ptr++]) & 0x0f;
+                pi7 = ((s->buf[stream_ptr]) >> 4) & 0x0f;
+                pi8 = (s->buf[stream_ptr++]) & 0x0f;
+
+                CHECK_PIXEL_PTR(rle_code * 8);
+
+                while (rle_code--) {
+                    rgb[pixel_ptr++] = pi1;
+                    rgb[pixel_ptr++] = pi2;
+                    rgb[pixel_ptr++] = pi3;
+                    rgb[pixel_ptr++] = pi4;
+                    rgb[pixel_ptr++] = pi5;
+                    rgb[pixel_ptr++] = pi6;
+                    rgb[pixel_ptr++] = pi7;
+                    rgb[pixel_ptr++] = pi8;
+                }
+            } else {
+                /* copy the same pixel directly to output 4 times */
+                rle_code *= 4;
+                CHECK_STREAM_PTR(rle_code);
+                CHECK_PIXEL_PTR(rle_code*2);
+
+                while (rle_code--) {
+                    rgb[pixel_ptr++] = ((s->buf[stream_ptr]) >> 4) & 0x0f;
+                    rgb[pixel_ptr++] = (s->buf[stream_ptr++]) & 0x0f;
+                }
+            }
+        }
+        row_ptr += row_inc;
+    }
 }
 
 static void qtrle_decode_8bpp(QtrleContext *s)
@@ -473,6 +559,12 @@ static int qtrle_decode_frame(AVCodecContext *avctx,
     case 4:
     case 36:
         qtrle_decode_4bpp(s);
+        /* make the palette available on the way out */
+        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
+        if (s->avctx->palctrl->palette_changed) {
+            s->frame.palette_has_changed = 1;
+            s->avctx->palctrl->palette_changed = 0;
+        }
         break;
 
     case 8:
-- 
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