Use libswscale in fish vhook.

Patch by
Victor Paesa <wzrlpy@arsystel.com>
Original thread:
Date: Aug 30, 2006 1:16 AM
Subject: Re: [Ffmpeg-devel] [PATCH] enable libswscale

Originally committed as revision 6128 to svn://svn.ffmpeg.org/ffmpeg/trunk

vhook/fish.c

@@ -45,6 +45,9 @@
 #include "framehook.h"
 #include "dsputil.h"
 #include "avformat.h"
+#include "swscale.h"
+
+static int sws_flags = SWS_BICUBIC;
 
 #define SCALEBITS 10
 #define ONE_HALF  (1 << (SCALEBITS - 1))
@@ -88,6 +91,9 @@ typedef struct {
     int64_t next_pts;
     int inset;
     int min_width;
+    struct SwsContext *toRGB_convert_ctx;
+    enum PixelFormat sws_pix_fmt;   // Sws_Context is opaque, we need to save
+    int sws_width, sws_height;      // this to check if we can re-use contexts
 } ContextInfo;
 
 static void dorange(const char *s, int *first, int *second, int maxval)
@@ -101,8 +107,13 @@ static void dorange(const char *s, int *first, int *second, int maxval)
 
 void Release(void *ctx)
 {
-    if (ctx)
+    ContextInfo *ci;
+    ci = (ContextInfo *) ctx;
+
+    if (ctx) {
+        sws_freeContext(ci->toRGB_convert_ctx);
         av_free(ctx);
+    }
 }
 
 int Configure(void **ctxp, int argc, char *argv[])
@@ -331,8 +342,37 @@ void Process(void *ctx, AVPicture *picture, enum PixelFormat pix_fmt, int width,
                 buf = av_malloc(size);
 
                 avpicture_fill(&picture1, buf, PIX_FMT_RGB24, width, height);
-                if (img_convert(&picture1, PIX_FMT_RGB24,
-                                picture, pix_fmt, width, height) >= 0) {
+
+                // if we already got a SWS context, let's realloc if is not re-useable
+                if (ci->toRGB_convert_ctx != NULL) {
+                    if ((ci->sws_pix_fmt != pix_fmt) ||
+                         (ci->sws_width != width) || (ci->sws_height != height)) {
+                        sws_freeContext(ci->toRGB_convert_ctx);
+                        ci->toRGB_convert_ctx = NULL;
+                    }
+                }
+                if (ci->toRGB_convert_ctx == NULL) {
+                    ci->sws_pix_fmt = pix_fmt;
+                    ci->sws_width = width;
+                    ci->sws_height = height;
+                    ci->toRGB_convert_ctx = sws_getContext(
+                                                     ci->sws_width, ci->sws_height,
+                                                     ci->sws_pix_fmt,
+                                                     ci->sws_width, ci->sws_height,
+                                                     PIX_FMT_RGB24,
+                                                     sws_flags, NULL, NULL, NULL);
+                    if (ci->toRGB_convert_ctx == NULL) {
+                        av_log(NULL, AV_LOG_ERROR,
+                               "Cannot initialize the toRGB conversion context\n");
+                        exit(1);
+                    }
+                }
+                // img_convert parameters are          2 first destination, then 4 source
+                // sws_scale   parameters are context, 4 first source,      then 2 destination
+                sws_scale(ci->toRGB_convert_ctx,
+                              picture->data, picture->linesize, 0, ci->sws_height,
+                              picture1.data, picture1.linesize);
+
                     /* Write out the PPM file */
 
                     FILE *f;
@@ -345,7 +385,6 @@ void Process(void *ctx, AVPicture *picture, enum PixelFormat pix_fmt, int width,
                         fwrite(buf, width * height * 3, 1, f);
                         fclose(f);
                     }
-                }
 
                 av_free(buf);
                 ci->next_pts = pts + ci->min_interval;