libxvid: Add SSIM displaying through a libxvidcore plugin

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/encoders.texi

@@ -1336,6 +1336,43 @@ be better than any of the two specified individually. In other
 words, the resulting quality will be the worse one of the two
 effects.
 
+@item ssim
+Set structural similarity (SSIM) displaying method. Possible values:
+
+@table @samp
+@item off
+Disable displaying of SSIM information.
+
+@item avg
+Output average SSIM at the end of encoding to stdout. The format of
+showing the average SSIM is:
+
+@example
+Average SSIM: %f
+@end example
+
+For users who are not familiar with C, %f means a float number, or
+a decimal (e.g. 0.939232).
+
+@item frame
+Output both per-frame SSIM data during encoding and average SSIM at
+the end of encoding to stdout. The format of per-frame information
+is:
+
+@example
+       SSIM: avg: %1.3f min: %1.3f max: %1.3f
+@end example
+
+For users who are not familiar with C, %1.3f means a float number
+rounded to 3 digits after the dot (e.g. 0.932).
+
+@end table
+
+@item ssim_acc
+Set SSIM accuracy. Valid options are integers within the range of
+0-4, while 0 gives the most accurate result and 4 computes the
+fastest.
+
 @end table
 
 @section png

libavcodec/libxvid.c

@@ -65,6 +65,8 @@ struct xvid_context {
     unsigned char *inter_matrix;   /**< I-Frame Quant Matrix */
     int lumi_aq;                   /**< Lumi masking as an aq method */
     int variance_aq;               /**< Variance adaptive quantization */
+    int ssim;                      /**< SSIM information display mode */
+    int ssim_acc;                  /**< SSIM accuracy. 0: accurate. 4: fast. */
 };
 
 /**
@@ -359,6 +361,7 @@ static av_cold int xvid_encode_init(AVCodecContext *avctx)  {
     xvid_plugin_2pass2_t rc2pass2     = { 0 };
     xvid_plugin_lumimasking_t masking_l = { 0 }; /* For lumi masking */
     xvid_plugin_lumimasking_t masking_v = { 0 }; /* For variance AQ */
+    xvid_plugin_ssim_t ssim           = { 0 };
     xvid_gbl_init_t xvid_gbl_init     = { 0 };
     xvid_enc_create_t xvid_enc_create = { 0 };
     xvid_enc_plugin_t plugins[7];
@@ -553,6 +556,17 @@ static av_cold int xvid_encode_init(AVCodecContext *avctx)  {
                "Both lumi_aq and variance_aq are enabled. The resulting quality"
                "will be the worse one of the two effects made by the AQ.\n");
 
+    /* SSIM */
+    if( x->ssim ) {
+        plugins[xvid_enc_create.num_plugins].func = xvid_plugin_ssim;
+        ssim.b_printstat = ( x->ssim == 2 );
+        ssim.acc         = x->ssim_acc;
+        ssim.cpu_flags   = xvid_gbl_init.cpu_flags;
+        ssim.b_visualize = 0;
+        plugins[xvid_enc_create.num_plugins].param = &ssim;
+        xvid_enc_create.num_plugins++;
+    }
+
     /* Frame Rate and Key Frames */
     xvid_correct_framerate(avctx);
     xvid_enc_create.fincr = avctx->time_base.num;
@@ -788,6 +802,11 @@ static av_cold int xvid_encode_close(AVCodecContext *avctx) {
 static const AVOption options[] = {
     { "lumi_aq",     "Luminance masking AQ", OFFSET(lumi_aq),     AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, VE },
     { "variance_aq", "Variance AQ",          OFFSET(variance_aq), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, VE },
+    { "ssim",        "Show SSIM information to stdout",       OFFSET(ssim),              AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, VE, "ssim" },
+        { "off",     NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN, INT_MAX, VE, "ssim" },
+        { "avg",     NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, INT_MIN, INT_MAX, VE, "ssim" },
+        { "frame",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN, INT_MAX, VE, "ssim" },
+    { "ssim_acc",    "SSIM accuracy",                         OFFSET(ssim_acc),          AV_OPT_TYPE_INT, { .i64 = 2 }, 0, 4, VE },
     { NULL },
 };