[FFmpeg-devel] [PATCH]lavf/matroskaenc: Do not allow -reserve_index_space 1

[Carl Eugen Hoyos]

2018-02-11 20:57 GMT+01:00 Nicolas George <george at nsup.org>:
> Carl Eugen Hoyos (2018-02-11):
>> 2018-02-11 20:23 GMT+01:00 Nicolas George <george at nsup.org>:
>> > Carl Eugen Hoyos (2018-02-11):
>> >> Attached patch fixes an assertion failure with the following command line:
>> >> $ ffmpeg -f lavfi -i testsrc -reserve_index_space 1 out.mkv
>>
>> > Reading the code, it is pretty obvious that 0 is a valid value and
>> > forbidding it would be bad.
>>
>> It is still the used default value...
>>
>> Uglier alternative attached.
>>
>> Carl Eugen
>
>> From 6a08d7cb89294b81e87dac93bbf58627e5d37cec Mon Sep 17 00:00:00 2001
>> From: Carl Eugen Hoyos <ceffmpeg at gmail.com>
>> Date: Sun, 11 Feb 2018 20:41:32 +0100
>> Subject: [PATCH] lavf/matroskaenc: Force the minimum value for
>>  -reserve_index_space to 2.
>>
>> Fixes an assertion failure:
>> Assertion size >= 2 failed at libavformat/matroskaenc.c:298
>> ---
>>  libavformat/matroskaenc.c |    2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
>> index f22c2ab..5950b4d 100644
>> --- a/libavformat/matroskaenc.c
>> +++ b/libavformat/matroskaenc.c
>> @@ -2001,6 +2001,8 @@ static int mkv_write_header(AVFormatContext *s)
>>      }
>>      if ((pb->seekable & AVIO_SEEKABLE_NORMAL) && mkv->reserve_cues_space) {
>>          mkv->cues_pos = avio_tell(pb);
>
>> +        if (mkv->reserve_cues_space == 1)
>> +            mkv->reserve_cues_space++;
>>          put_ebml_void(pb, mkv->reserve_cues_space);
>
> I would have written it:
>
>         put_ebml_void(pb, FFMAX(2, mkv->reserve_cues_space));
>
> That is more or less equivalent to this patch.

Applied my variant as I consider it (very slightly) more readable.

Thank you, Carl Eugen