[FFmpeg-devel,02/15] avformat/matroskaenc: Fix BlockGroup size calculation

Submitted by Andreas Rheinhardt on April 19, 2019, 11:40 p.m.

Details

Message ID 20190419234110.32980-2-andreas.rheinhardt@gmail.com
State New
Headers show

Commit Message

Andreas Rheinhardt April 19, 2019, 11:40 p.m.
The earlier code included the size of the BlockGroup's length field and
the EBML ID in the calculation of the size for the payload and ignored
the size of the  duration's length field. This meant that Blockgroups
corresponding to packets with size 2^(7n) - 17 - n - i, i = 0,..., n - 1,
n = 1,..., 8 (i.e. 110, 16364, 16365, 2097130..2097132, ...) were written
with length fields that are unnecessarily long.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
---
 libavformat/matroskaenc.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

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diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index c006cbf35c..1849ae3333 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -2059,9 +2059,7 @@  static int mkv_blockgroup_size(int pkt_size)
     int size = pkt_size + 4;
     size += ebml_num_size(size);
     size += 2;              // EBML ID for block and block duration
-    size += 8;              // max size of block duration
-    size += ebml_num_size(size);
-    size += 1;              // blockgroup EBML ID
+    size += 9;              // max size of block duration incl. length field
     return size;
 }