[mythtv-users] Some Videos Not Seen by Scan

[Michael T. Dean]

On 08/09/2017 05:05 PM, Mark Perkins wrote:
> On 10 August 2017 12:01:01 am "Michael T. Dean" wrote:
>
>> On 08/09/2017 10:04 AM, John Pilkington wrote:
>>> Or search 'mythtv video hash'
>>>
>>> Perhaps your ffmpeg processes gave identical results.
>> Yes, this is most likely the issue. The hash that's created to identify
>> unique videos is done with only a small part of the file at the
>> beginning and the end (because reading multiple gigabytes per file from
>> disk and running the entire video through a hash algorithm would take
>> ages to complete).  It's likely your test files are just too close to
>> the same, so are being considered the same and only showed once (one or
>> the other is shown and the one not shown is ignored).
>>
>> There's no way to "fix" this as it's working as designed (and typical
>> use cases don't involve multiple almost identical files).
> I wonder if the hash algorithm could be updated to include the file
> creation date or something else similar to help mitigate this type of overlap?

We're using the same hash algorithm used by other projects, the 
OpenSubtitles hashing algorithm, which is based on Media Player Classic. 
http://trac.opensubtitles.org/projects/opensubtitles/wiki/HashSourceCodes

Any changes make ours a custom hash, with custom bugs and custom testing 
and custom maintenance required.  It's also quite possible that some 
people are using the hash with other programs.

Mike