[FFmpeg-devel] [PATCH 2/2] avformat: Make AVChapter.id an int64_t on next major bump

[Andreas Rheinhardt]

Anton Khirnov:
> Quoting Andreas Rheinhardt (2021-03-16 09:29:53)
>> 64 bits are needed in order to retain the uid values of Matroska
>> chapters; the type is kept signed because the semantics of NUT chapters
>> depend upon whether the id is > 0 or < 0.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>> Apologies for being so late.
>>
>>  doc/APIchanges            | 4 ++++
>>  libavformat/aadec.c       | 2 +-
>>  libavformat/avformat.h    | 4 ++++
>>  libavformat/internal.h    | 4 ++++
>>  libavformat/matroskaenc.c | 4 ++++
>>  libavformat/nutdec.c      | 4 ++--
>>  libavformat/utils.c       | 4 ++++
>>  libavformat/version.h     | 5 ++++-
>>  8 files changed, 27 insertions(+), 4 deletions(-)
>>
>> diff --git a/doc/APIchanges b/doc/APIchanges
>> index c0d955b1fa..8b93adebe1 100644
>> --- a/doc/APIchanges
>> +++ b/doc/APIchanges
>> @@ -15,6 +15,10 @@ libavutil:     2017-10-21
>>  
>>  API changes, most recent first:
>>  
>> +2021-03-16 - xxxxxxxxxx - lavf 58.75.100  - avformat.h
>> +  AVChapter.id will be changed from int to int64_t
>> +  on the next major version bump.
>> +
>>  2021-03-12 - xxxxxxxxxx - lavc 58.131.100 - avcodec.h codec.h
>>    Add a get_encode_buffer callback to AVCodecContext, similar to
>>    get_buffer2 but for encoders.
>> diff --git a/libavformat/aadec.c b/libavformat/aadec.c
>> index e88cdb89df..80ca2c12d7 100644
>> --- a/libavformat/aadec.c
>> +++ b/libavformat/aadec.c
>> @@ -222,7 +222,7 @@ static int aa_read_header(AVFormatContext *s)
>>      c->content_end = start + largest_size;
>>  
>>      while ((chapter_pos = avio_tell(pb)) >= 0 && chapter_pos < c->content_end) {
>> -        int chapter_idx = s->nb_chapters;
>> +        unsigned chapter_idx = s->nb_chapters;
> 
> unrelated?
> 
The chapter ids created by aadec are just 0,1,... And in the
hypothetical scenario that there are more than INT_MAX of them the
INT_MAX+1U chapter would have a negative id if I didn't change it to
unsigned above. (I don't think it can happen, but nb_chapters is an
unsigned, so it is better anyway.)

- Andreas