[FFmpeg-devel] avformat/mxfenc: fix stored/sampled/displayed width/height

[Jerome Martinez <jerome@mediaarea.net>]

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Before the patch:
- stored values were rounded to upper 16 multiple also for formats not 
using macroblocks (should be st->codecpar->width and 
st->codecpar->height when not MPEG formats; note that I found no other 
muxer doing the rounding for AVC, only for MPEG-2 Video, but I find no 
reason in specs for doing the difference so I kept the rounding for AVC)
- sampled and displayed widths were stored width (should be 
st->codecpar->width like it is already done for height, with the 
DV50/100 exception)

Could be tested with e.g.
- fixed stored width (1912 instead of 1920) and height (1080 instead of 
1088) not multiple of 16 :
ffmpeg -f lavfi -i testsrc=duration=1:size=1912x1080 -c:v jpeg2000 
test_prores.mxf
- fixed sampled/displayed width (1912 instead of 1920):
ffmpeg -f lavfi -i testsrc=duration=1:size=1912x1080 -c:v mpeg2video 
test_mpeg2video.mxf

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From cda353059886182aab2e258023c4d027c448344b Mon Sep 17 00:00:00 2001
From: Jerome Martinez <jerome@mediaarea.net>
Date: Sat, 14 Jan 2023 13:32:36 +0100
Subject: [PATCH] avformat/mxfenc: fix stored/sampled/displayed width/height

Stored values are rounded to upper 16 multiple only for MPEG related formats
Sampled and displayed widths are codecpar ones (with DV exception)
---
 libavformat/mxfenc.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 58c551c83c..0b7e83ba4d 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -1109,8 +1109,9 @@ static int64_t mxf_write_cdci_common(AVFormatContext *s, AVStream *st, const UID
 {
     MXFStreamContext *sc = st->priv_data;
     AVIOContext *pb = s->pb;
-    int stored_width = 0;
-    int stored_height = (st->codecpar->height+15)/16*16;
+    int stored_width = st->codecpar->width;
+    int stored_height = st->codecpar->height;
+    int display_width;
     int display_height;
     int f1, f2;
     const MXFCodecUL *color_primaries_ul;
@@ -1129,12 +1130,25 @@ static int64_t mxf_write_cdci_common(AVFormatContext *s, AVStream *st, const UID
         else if (st->codecpar->height == 720)
             stored_width = 1280;
     }
-    if (!stored_width)
-        stored_width = (st->codecpar->width+15)/16*16;
+    display_width = stored_width;
 
+    switch (st->codecpar->codec_id) {
+    case AV_CODEC_ID_MPEG2VIDEO:
+    case AV_CODEC_ID_DVVIDEO:
+    case AV_CODEC_ID_H264:
+        //Based on 16x16 macroblocks
+        stored_width = (stored_width+15)/16*16;
+        stored_height = (stored_height+15)/16*16;
+        break;
+    default:
+        break;
+    }
+
+    //Stored width
     mxf_write_local_tag(s, 4, 0x3203);
     avio_wb32(pb, stored_width);
 
+    //Stored height
     mxf_write_local_tag(s, 4, 0x3202);
     avio_wb32(pb, stored_height>>sc->interlaced);
 
@@ -1154,7 +1168,7 @@ static int64_t mxf_write_cdci_common(AVFormatContext *s, AVStream *st, const UID
 
     //Sampled width
     mxf_write_local_tag(s, 4, 0x3205);
-    avio_wb32(pb, stored_width);
+    avio_wb32(pb, display_width);
 
     //Samples height
     mxf_write_local_tag(s, 4, 0x3204);
@@ -1168,8 +1182,9 @@ static int64_t mxf_write_cdci_common(AVFormatContext *s, AVStream *st, const UID
     mxf_write_local_tag(s, 4, 0x3207);
     avio_wb32(pb, 0);
 
+    //Display width
     mxf_write_local_tag(s, 4, 0x3209);
-    avio_wb32(pb, stored_width);
+    avio_wb32(pb, display_width);
 
     if (st->codecpar->height == 608) // PAL + VBI
         display_height = 576;
@@ -1178,6 +1193,7 @@ static int64_t mxf_write_cdci_common(AVFormatContext *s, AVStream *st, const UID
     else
         display_height = st->codecpar->height;
 
+    //Display height
     mxf_write_local_tag(s, 4, 0x3208);
     avio_wb32(pb, display_height>>sc->interlaced);
 
-- 
2.13.3.windows.1


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