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

[Andreas Rheinhardt]

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
> 
Ping.

- Andreas