[FFmpeg-devel] checked region version in dvbsubdec.c

anshul anshul.ffmpeg at gmail.com
Mon Apr 28 10:33:04 CEST 2014

On 04/22/2014 07:09 PM, Michael Niedermayer wrote:
> On Tue, Apr 15, 2014 at 06:37:38PM +0530, anshul wrote:
>> Hi
>> I referred ETSI EN 300 743 V1.3.1 (2006-11) for dvb subtitle.
>> This document they say that ...
>>    region_version_number: This indicates the version of this region.
>>     The version number is incremented (modulo 16) if one or more of
>>      the following conditions is true :
>>       -> the region_fill_flag is set;
>>       -> the regions CLUT family has been modified;
>>       -> the region has a non-zero length object list.
>> so I have changed code to not check anything if version number are same.
> The version could also match when streams are concatenated
> so i would suggest that more is checked than the 4 bit version
> [...]
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Sorry for too late reply,

version of two stream can only match if Page composition segment of 
Second stream
has not been received yet  and end of display set segment of first 
stream is not received.

even if version match that does mean we have not received page 
composition segment
of second stream yet, so this region segment is invalid if it comes 
before page composition segment.

Since Region segment to parsed are mention in page composition segment, 
there would be a problem
if version does not match of second stream and first stream.

concatenation should be considered as special behavior and all segment 
information of previous
component should be reset.

I don't know where to start for that, may be some streams where you get 
problem while concatenation
could help me.


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