[FFmpeg-devel] [PATCH 1/2] avformat/microdvd: Use \n instead of \0 to end file header

[Andreas Rheinhardt]

Up until now, the microdvd demuxer uses av_strdup() to allocate the
extradata from a string; its length is set to strlen() + 1, i.e.
including the \0 at the end. Upon remuxing, the muxer would simply copy
the extradata at the beginning, including the \0.

This commit changes this by not adding the \0 to the size of the
extradata; the muxer now delimits extradata by inserting a \n. This
required to change the subtitles-microdvd-remux FATE-test.

Furthermore, the extradata is now allocated with zeroed padding.

The microdvd decoder is not affected by this, as it didn't use the size
of the extradata at all, but treated it as a C-string.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavformat/microdvddec.c         |   9 +++++----
 libavformat/microdvdenc.c         |   1 +
 tests/ref/fate/sub-microdvd-remux | Bin 416 -> 416 bytes
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/libavformat/microdvddec.c b/libavformat/microdvddec.c
index ca9086afe9..08e6fca09c 100644
--- a/libavformat/microdvddec.c
+++ b/libavformat/microdvddec.c
@@ -117,10 +117,11 @@ static int microdvd_read_header(AVFormatContext *s)
                 continue;
             }
             if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
-                st->codecpar->extradata = av_strdup(line + 11);
-                if (!st->codecpar->extradata)
-                    return AVERROR(ENOMEM);
-                st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;
+                int ret, size = strlen(line + 11);
+                ret = ff_alloc_extradata(st->codecpar, size);
+                if (ret < 0)
+                    return ret;
+                memcpy(st->codecpar->extradata, line + 11, size);
                 continue;
             }
         }
diff --git a/libavformat/microdvdenc.c b/libavformat/microdvdenc.c
index 04f475b645..6639651e02 100644
--- a/libavformat/microdvdenc.c
+++ b/libavformat/microdvdenc.c
@@ -36,6 +36,7 @@ static int microdvd_write_header(struct AVFormatContext *s)
     if (par->extradata && par->extradata_size > 0) {
         avio_write(s->pb, "{DEFAULT}{}", 11);
         avio_write(s->pb, par->extradata, par->extradata_size);
+        avio_w8(s->pb, '\n');
         avio_flush(s->pb);
     }
 
diff --git a/tests/ref/fate/sub-microdvd-remux b/tests/ref/fate/sub-microdvd-remux
index a71da99031fdc4bff13ea7124c046e761a650dc8..92ff233f56b6fec33d4e9e0698ec43377ea5fab7 100644
GIT binary patch
delta 12
TcmZ3$ynuOvE+f}Qy&^^c7%l^0

delta 12
TcmZ3$ynuOvE+fN6y&^^c7yJWP

-- 
2.20.1