[pHash-support] mpeg1 and mpeg2 codecs are partially working with pHash

[Evan Klinger]

It's the same.


On Fri, Nov 8, 2013 at 9:58 AM, Pratik Bhoir <pbhoir at blue-efficience.com>wrote:

> Hi Evan,
>
> Thank you for your reply.
>
> Can you please clarify if you are using the same key frame extraction
> algorithm in pHash Pro? or this issue is fixed in Pro version?
>
> Thank you,
> Pratik
>
>
> On Fri, Nov 8, 2013 at 6:38 PM, Evan Klinger <eklinger at phash.org> wrote:
>
>> Hi Pratik,
>>
>> Unfortunately this is likely due to the key frame extraction algorithm
>> used in pHash GPL for the video hash. We do not have a fix for it at this
>> time.
>>
>> Thank you
>> Evan
>>
>>
>> On Wed, Oct 30, 2013 at 9:53 AM, Pratik Bhoir <pbhoir at blue-efficience.com
>> > wrote:
>>
>>> Hello pHash team,
>>>
>>> My company is searching for a video fingerprint technology to automate
>>> more our processes.
>>> Currently we are testing pHash open source for video hashing and
>>> depending on the results we might be interested in buying pHash Pro licence.
>>>
>>> We came across what looks like to be an issue that pHash is not
>>> calculating enough hash (only one hash value, irrespective of length of the
>>> video) values for
>>> mpeg1 and mpeg2 codecs.
>>>
>>> Brief description of the issue:
>>>
>>> System : Ubuntu 12.04 LTS
>>> phash 0.9.6 (configured only with --enable-shared option)
>>> CImg 1.4.9 (installed directly from Ubuntu repository)
>>> ffmpeg 2.1  (configured only with --enable-shared option)
>>>
>>> I have also tried all available versions of ffmpeg with the same result.
>>>
>>> Though I edited one file before testing video hash,
>>> 1. cimgffmpeg.cpp : I edited this file because initially I was getting
>>> segfault while executing test_video.
>>>                               I edited the function long
>>> GetNumberVideoFrames(const char *file) and float fps(const char *filename),
>>> in both functions I assigned AVformatContext *pFormatCtx = NULL; as
>>> mentioned in one of the support archive and it worked. URL:
>>> http://lists.phash.org/htdig.cgi/phash-support-phash.org/2013-January/000140.html
>>>
>>>
>>> Using the examples provided in pHash package, all the video coding
>>> formats that I have tested are working well except  mpeg1 and mpeg2.
>>> I have tried different videos with various lengths(5min, 20min and 45
>>> min) but result is always one hash value for mpeg1 and mpeg2.
>>>
>>> Can you please look upon this issue and tell me where is the problem?
>>>
>>> Thank you for your time and help,
>>>
>>> - Pratik
>>>
>>> _______________________________________________
>>> pHash-support mailing list
>>> pHash-support at lists.phash.org
>>> http://lists.phash.org/listinfo.cgi/phash-support-phash.org
>>>
>>>
>>
>
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