Re: [FFmpeg-devel] [PATCH]lavc/pgssubdec: Fix palette colourspace

[Carl Eugen Hoyos]

On Sunday 17 April 2016 08:41:32 pm Jan Ekstrom wrote:
> Yes, the YCbCr values in palettes are matched accordingly against the
> video stream. As per the specification:
> "Y, Cr and Cb shall have the same color matrix as the associated HDMV
> Video stream: 525-60/625-50 (Rec.601); 1080i, 720p (ITU-709)"

Does attached make it better?

Carl Eugen

diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
index 07a2a78..29fc09a 100644
--- a/libavcodec/pgssubdec.c
+++ b/libavcodec/pgssubdec.c
@@ -96,6 +96,7 @@ typedef struct PGSSubContext {
     PGSSubPalettes     palettes;
     PGSSubObjects      objects;
     int forced_subs_only;
+    int hdtv;
 } PGSSubContext;
 
 static void flush_cache(AVCodecContext *avctx)
@@ -136,6 +137,9 @@ static PGSSubPalette * find_palette(int id, PGSSubPalettes 
*palettes)
 
 static av_cold int init_decoder(AVCodecContext *avctx)
 {
+    PGSSubContext *ctx = avctx->priv_data;
+    ctx->hdtv          = -1;
+
     avctx->pix_fmt     = AV_PIX_FMT_PAL8;
 
     return 0;
@@ -354,8 +358,13 @@ static int parse_palette_segment(AVCodecContext *avctx,
         cb        = bytestream_get_byte(&buf);
         alpha     = bytestream_get_byte(&buf);
 
-        YUV_TO_RGB1(cb, cr);
-        YUV_TO_RGB2(r, g, b, y);
+        if (ctx->hdtv > 0) {
+            YUV_TO_RGB1_CCIR(cb, cr);
+            YUV_TO_RGB2_CCIR(r, g, b, y);
+        } else {
+            YUV_TO_RGB1(cb, cr);
+            YUV_TO_RGB2(r, g, b, y);
+        }
 
         ff_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, 
alpha);
 
@@ -387,6 +396,11 @@ static int parse_presentation_segment(AVCodecContext 
*avctx,
     // Video descriptor
     int w = bytestream_get_be16(&buf);
     int h = bytestream_get_be16(&buf);
+    if (h > 625 && ctx->hdtv == -1) {
+        ctx->hdtv = 1;
+    } else {
+        ctx->hdtv = 0;
+    }
 
     ctx->presentation.pts = pts;
 

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