fixed some return values and deprecated CODEC_TYPE_VIDEO.

dithering (faster) along a linear gradient now.

Originally committed as revision 24898 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/a64colors.h

+/*
+ * a64 video encoder - tables used by 64enc
+ * Copyright (c) 2009 Tobias Bindhammer
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * a64 video encoder - c64 colors in rgb
+ */
+
+#ifndef AVCODEC_A64COLORS_H
+#define AVCODEC_A64COLORS_H
+
+/* c64 palette in RGB */
+static const uint8_t a64_palette[16][3] = {
+    {0x00, 0x00, 0x00},
+    {0xff, 0xff, 0xff},
+    {0x68, 0x37, 0x2b},
+    {0x70, 0xa4, 0xb2},
+    {0x6f, 0x3d, 0x86},
+    {0x58, 0x8d, 0x43},
+    {0x35, 0x28, 0x79},
+    {0xb8, 0xc7, 0x6f},
+    {0x6f, 0x4f, 0x25},
+    {0x43, 0x39, 0x00},
+    {0x9a, 0x67, 0x59},
+    {0x44, 0x44, 0x44},
+    {0x6c, 0x6c, 0x6c},
+    {0x9a, 0xd2, 0x84},
+    {0x6c, 0x5e, 0xb5},
+    {0x95, 0x95, 0x95},
+};
+
+#endif /* AVCODEC_A64COLORS_H */

libavcodec/a64enc.h

@@ -45,6 +45,8 @@ typedef struct A64Context {
     int *mc_meta_charset;
     int *mc_charmap;
     int *mc_best_cb;
+    int *mc_charset;
+    int mc_luma_vals[5];
 } A64Context;
 
 #endif /* AVCODEC_A64ENC_H */

libavcodec/a64multienc.c

@@ -25,11 +25,16 @@
  */
 
 #include "a64enc.h"
+#include "a64colors.h"
 #include "a64tables.h"
 #include "elbg.h"
 #include "libavutil/intreadwrite.h"
 
-#define DITHERSTEPS 8
+#define DITHERSTEPS   8
+#define CHARSET_CHARS 256
+
+/* gray gradient */
+static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
 
 static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
 {
@@ -63,64 +68,72 @@ static void render_charset(AVCodecContext *avctx, uint8_t *charset,
     A64Context *c = avctx->priv_data;
     uint8_t row1;
     int charpos, x, y;
-    int pix;
-    int dither;
-    int index1, index2;
+    int a, b;
+    uint8_t pix;
     int lowdiff, highdiff;
-    int maxindex = c->mc_use_5col + 3;
-    int maxsteps = DITHERSTEPS * maxindex + 1;
     int *best_cb = c->mc_best_cb;
+    static uint8_t index1[256];
+    static uint8_t index2[256];
+    static uint8_t dither[256];
+    int i;
+    int distance;
 
-    /* now reduce colors first */
-    for (x = 0; x < 256 * 32; x++) best_cb[x] = best_cb[x] * maxsteps / 255;
-
+    /* generate lookup-tables for dither and index before looping */
+    i = 0;
+    for (a=0; a < 256; a++) {
+        if(i < 4 && a == c->mc_luma_vals[i+1]) {
+            distance = c->mc_luma_vals[i+1] - c->mc_luma_vals[i];
+            for(b = 0; b <= distance; b++) {
+                  dither[c->mc_luma_vals[i]+b] = b * (DITHERSTEPS - 1) / distance;
+            }
+            i++;
+        }
+        if(i >=4 ) dither[a] = 0;
+        index1[a] = i;
+        index2[a] = FFMIN(i+1, 4);
+    }
     /* and render charset */
-    for (charpos = 0; charpos < 256; charpos++) {
+    for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
         lowdiff  = 0;
         highdiff = 0;
         for (y = 0; y < 8; y++) {
             row1 = 0;
             for (x = 0; x < 4; x++) {
                 pix = best_cb[y * 4 + x];
-                dither = pix % DITHERSTEPS;
-                index1 = pix / DITHERSTEPS;
-                index2 = FFMIN(index1 + 1, maxindex);
 
-                if (pix > 3 * DITHERSTEPS)
-                    highdiff += pix - 3 * DITHERSTEPS;
-                if (pix < DITHERSTEPS)
-                    lowdiff += DITHERSTEPS - pix;
+                /* accumulate error for brightest/darkest color */
+                if (index1[pix] >= 3)
+                    highdiff += pix - c->mc_luma_vals[3];
+                if (index1[pix] < 1)
+                    lowdiff += c->mc_luma_vals[1] - pix;
 
                 row1 <<= 2;
-                if (prep_dither_patterns[dither][y & 3][x & 3]) {
-                    row1 |= 3-(index2 & 3);
-                } else {
-                    row1 |= 3-(index1 & 3);
-                }
+
+                if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
+                    row1 |= 3-(index2[pix] & 3);
+                else
+                    row1 |= 3-(index1[pix] & 3);
             }
-            charset[y] = row1;
+            charset[y+0x000] = row1;
         }
-
-        /* are we in 5col mode and need to adjust pixels? */
-        if (c->mc_use_5col && highdiff > 0 && lowdiff > 0) {
+        /* do we need to adjust pixels? */
+        if (highdiff > 0 && lowdiff > 0) {
             if (lowdiff > highdiff) {
                 for (x = 0; x < 32; x++)
-                    best_cb[x] = FFMIN(3 * DITHERSTEPS, best_cb[x]);
+                    best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
             } else {
                 for (x = 0; x < 32; x++)
-                    best_cb[x] = FFMAX(DITHERSTEPS, best_cb[x]);
+                    best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
             }
-            charpos--;          /* redo char */
+            charpos--;          /* redo now adjusted char */
+        /* no adjustment needed, all fine */
         } else {
             /* advance pointers */
             best_cb += 32;
             charset += 8;
 
-            if (highdiff > 0) {
-                colrammap[charpos] = 0x9;
-            } else {
-                colrammap[charpos] = 0x8;
-            }
+            /* remember colorram value */
+            colrammap[charpos] = (highdiff > 0) + 8;
         }
     }
 }
@@ -131,12 +144,14 @@ static av_cold int a64multi_close_encoder(AVCodecContext *avctx)
     av_free(c->mc_meta_charset);
     av_free(c->mc_best_cb);
     av_free(c->mc_charmap);
+    av_free(c->mc_charset);
     return 0;
 }
 
 static av_cold int a64multi_init_encoder(AVCodecContext *avctx)
 {
     A64Context *c = avctx->priv_data;
+    int a;
     av_lfg_init(&c->randctx, 1);
 
     if (avctx->global_quality < 1) {
@@ -147,11 +162,19 @@ static av_cold int a64multi_init_encoder(AVCodecContext *avctx)
 
     av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
 
+    /* precalc luma values for later use */
+    for (a = 0; a < 5; a++) {
+        c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
+                           a64_palette[mc_colors[a]][1] * 0.59 +
+                           a64_palette[mc_colors[a]][2] * 0.11;
+    }
+
     c->mc_frame_counter = 0;
     c->mc_use_5col      = avctx->codec->id == CODEC_ID_A64_MULTI5;
     c->mc_meta_charset  = av_malloc(32000 * c->mc_lifetime * sizeof(int));
-    c->mc_best_cb       = av_malloc(256 * 32 * sizeof(int));
+    c->mc_best_cb       = av_malloc(CHARSET_CHARS * 32 * sizeof(int));
     c->mc_charmap       = av_malloc(1000 * c->mc_lifetime * sizeof(int));
+    c->mc_charset       = av_malloc(0x800 * sizeof(uint8_t));
 
     avcodec_get_frame_defaults(&c->picture);
     avctx->coded_frame            = &c->picture;
@@ -188,7 +211,7 @@ static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,
 
     if (req_size > buf_size) {
         av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", req_size, buf_size);
-        return -1;
+        return AVERROR(EINVAL);
     }
     /* fill up mc_meta_charset with framedata until lifetime exceeds */
     if (c->mc_frame_counter < c->mc_lifetime) {
@@ -203,8 +226,8 @@ static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,
     /* lifetime exceeded so now convert X frames at once */
     if (c->mc_frame_counter == c->mc_lifetime && c->mc_lifetime > 0) {
         c->mc_frame_counter = 0;
-        ff_init_elbg(meta, 32, 1000 * c-> mc_lifetime, best_cb, 256, 5, charmap, &c->randctx);
-        ff_do_elbg  (meta, 32, 1000 * c-> mc_lifetime, best_cb, 256, 5, charmap, &c->randctx);
+        ff_init_elbg(meta, 32, 1000 * c-> mc_lifetime, best_cb, CHARSET_CHARS, 5, charmap, &c->randctx);
+        ff_do_elbg  (meta, 32, 1000 * c-> mc_lifetime, best_cb, CHARSET_CHARS, 5, charmap, &c->randctx);
 
         render_charset(avctx, buf, colrammap);
 
@@ -223,7 +246,7 @@ static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,
 
 AVCodec a64multi_encoder = {
     .name           = "a64multi",
-    .type           = CODEC_TYPE_VIDEO,
+    .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_A64_MULTI,
     .priv_data_size = sizeof(A64Context),
     .init           = a64multi_init_encoder,
@@ -236,7 +259,7 @@ AVCodec a64multi_encoder = {
 
 AVCodec a64multi5_encoder = {
     .name           = "a64multi5",
-    .type           = CODEC_TYPE_VIDEO,
+    .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_A64_MULTI5,
     .priv_data_size = sizeof(A64Context),
     .init           = a64multi_init_encoder,

libavcodec/a64tables.h

@@ -32,7 +32,8 @@
 /**
  * dither patterns used vor rendering the multicolor charset
  */
-static const uint8_t prep_dither_patterns[9][4][4] = {
+
+static const uint8_t multi_dither_patterns[9][4][4] = {
     {
      {0, 0, 0, 0},
      {0, 0, 0, 0},

libavformat/a64.c

@@ -46,7 +46,7 @@ static int a64_write_header(struct AVFormatContext *s)
         header[4] = 3;
         break;
     default:
-        return -1;
+        return AVERROR(EINVAL);
         break;
     }
     put_buffer(s->pb, header, 2);