[FFmpeg-devel] [PATCH 3/5] libxvid: Add SSIM displaying through an libxvidcore plugin

[Timothy Gu]

---
 doc/encoders.texi    | 37 +++++++++++++++++++++++++++++++++++++
 libavcodec/libxvid.c | 19 +++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/doc/encoders.texi b/doc/encoders.texi
index a42e7ba..6286b9c 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -1356,6 +1356,43 @@ Variance masking.
 
 @end table
 
+ at item ssim
+Set structural similarity (SSIM) displaying method. Possible values:
+
+ at table @samp
+ at item off
+Disable displaying of SSIM information.
+
+ at item avg
+Output average SSIM at the end of encoding to stdout. The format of
+showing the average SSIM is:
+
+ at example
+Average SSIM: %f
+ at end example
+
+For users who are not familiar with C, %f means a float number, or
+a decimal (e.g. 0.939232).
+
+ at 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:
+
+ at example
+       SSIM: avg: %1.3f min: %1.3f max: %1.3f
+ at 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).
+
+ at end table
+
+ at 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
diff --git a/libavcodec/libxvid.c b/libavcodec/libxvid.c
index 15b3734..f3b3db5 100644
--- a/libavcodec/libxvid.c
+++ b/libavcodec/libxvid.c
@@ -64,6 +64,8 @@ struct xvid_context {
     unsigned char *intra_matrix;   /**< P-Frame Quant Matrix */
     unsigned char *inter_matrix;   /**< I-Frame Quant Matrix */
     int lumi_masking_mode;         /**< Luminance masking mode */
+    int ssim;                      /**< SSIM information display mode */
+    int ssim_acc;                  /**< SSIM accuracy. 0: accurate. 4: fast. */
 };
 
 /**
@@ -357,6 +359,7 @@ static av_cold int xvid_encode_init(AVCodecContext *avctx)  {
     struct xvid_ff_pass1 rc2pass1     = { 0 };
     xvid_plugin_2pass2_t rc2pass2     = { 0 };
     xvid_plugin_lumimasking_t masking = { 0 };
+    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];
@@ -538,6 +541,17 @@ static av_cold int xvid_encode_init(AVCodecContext *avctx)  {
         xvid_enc_create.num_plugins++;
     }
 
+    /* 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;
@@ -775,6 +789,11 @@ static const AVOption options[] = {
         { "off",           NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN, INT_MAX, VE, "lumi_masking_mode" },
         { "lumi",          NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, INT_MIN, INT_MAX, VE, "lumi_masking_mode" },
         { "variance",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN, INT_MAX, VE, "lumi_masking_mode" },
+    { "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 },
 };
 
-- 
1.8.1.2