[FFmpeg-devel] [PATCH]Write tiff aspect ratio by default instead of dpi

[Carl Eugen Hoyos]

On Thursday 03 April 2014 05:29:09 am Michael Niedermayer wrote:
> > -    uint32_t res[2] = { s->dpi, 1 };    // image resolution (72/1)
> > +    uint32_t resx[2] = { s->dpi ? s->dpi :
> > avctx->sample_aspect_ratio.den, 1 }; +    uint32_t resy[2] = { s->dpi ?
> > s->dpi : avctx->sample_aspect_ratio.num, 1 };
>
> i think this is wrong
> shouldnt the dpi be adjusted when the aspect differs from 1:1

New patch attached which is supported by more image viewers 
on my system.
It's now: Consider aspect ratio when writing tiff dpi.

Please comment, Carl Eugen
-------------- next part --------------
diff --git a/libavcodec/tiffenc.c b/libavcodec/tiffenc.c
index 7b1e510..01e6168 100644
--- a/libavcodec/tiffenc.c
+++ b/libavcodec/tiffenc.c
@@ -436,6 +436,13 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     add_entry1(s, TIFF_ROWSPERSTRIP, TIFF_LONG,     s->rps);
     add_entry(s,  TIFF_STRIP_SIZE,   TIFF_LONG,     strips, s->strip_sizes);
     add_entry(s,  TIFF_XRES,         TIFF_RATIONAL, 1,      res);
+    if (avctx->sample_aspect_ratio.num > 0 &&
+        avctx->sample_aspect_ratio.den > 0) {
+        AVRational y = av_mul_q((AVRational) { s->dpi, 1 },
+                                avctx->sample_aspect_ratio);
+        res[0] = y.num;
+        res[1] = y.den;
+    }
     add_entry(s,  TIFF_YRES,         TIFF_RATIONAL, 1,      res);
     add_entry1(s, TIFF_RES_UNIT,     TIFF_SHORT,    2);
 
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 6472c0f..ca5ab26 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -30,7 +30,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR 55
 #define LIBAVCODEC_VERSION_MINOR  57
-#define LIBAVCODEC_VERSION_MICRO 100
+#define LIBAVCODEC_VERSION_MICRO 101
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \