[FFmpeg-user] FFMPEG Signature Error

[Dave Rice]

Hi Nicolas,

> On Feb 20, 2018, at 6:04 AM, Nicolas Briand <nicolas.briand at ericsson.com> wrote:
> 
> Hi,
> 
> I was reading the FFMPEG manual and one function interest me. This function is called “Signature”.
> 
> I downloaded the last FFMPEG build static and I read the doc inside the .rar. There is two examples given, we have :
> 
> “To calculate the signature of an input video and store it in signature.bin:
> ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f null -
> To detect whether two videos match and store the signatures in XML format in signature0.xml and signature1.xml:
> ffmpeg -i input1.mkv -i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f null –“
> 
> The first one currently works, I took one .mp4 video, and I got a signature.xml.
> 
> But the second one doesn’t work. I would like to know if this is normal or a bug, if anyone has the answer.
> 
> This is the error generated :
> ‘[Parsed_signature_0 @ 00000000004a31c0] The filename must contain %d or %0nd, if you have more than one input.
> [AVFilterGraph @ 000000000273d340] Error initializing filter 'signature' with args 'nb_inputs=2:detectmode=full:format=xml:filename=signaturev -f nullÔÇôÔÇ£'
> Error initializing complex filters.
> Invalid argument’

Perhaps the issue is that you’re naming the output of the signature filter of the first command as "signature%d.xml” but then the input to the signature filter in the second command as “signaturev”.

For use of this filter I also recommend this blogpost: https://ndsr.americanarchive.org/2017/04/20/adventures-in-perceptual-hashing/ <https://ndsr.americanarchive.org/2017/04/20/adventures-in-perceptual-hashing/>

[…]

Best Regards,
Dave Rice