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Audio Forensic Expert

Rega

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
18
Location
india
Good afternoon all members and best wishes for the upcoming new year 2018. I need some help relating to an audio file. So I request any member who is into forensics to kindly respond.
 

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
18
Location
india
Good day all, reviving my old thread. I have a question regarding audio editing. If a certain audio file say of wav format is edited by either deletions or making additions, this editing can be detected by way of critical listening whereby, as claimed, certain clicks or other sounds will be heard where the editing has been done. Further it is claimed that spectrographic analysis using softwares like audacity soundforge, etc. editing can be confirmed as the graph will show peculiar breaks.
It has been claimed by some that after editing if the file format is converted several times and than it is converted back to its original format and attributes, the editing becomes impossible to detect. I want to know how far this is true? Is there any software which can automatically detect editing without the use of critical listening and manually searching for edits in the spectrograph.
I will be grateful If anyone can throw light on this issue
Thanks in advance
Regards
 

rikhav

Well-Known Member
Joined
Mar 27, 2008
Messages
2,732
Points
113
Good day all, reviving my old thread. I have a question regarding audio editing. If a certain audio file say of wav format is edited by either deletions or making additions, this editing can be detected by way of critical listening whereby, as claimed, certain clicks or other sounds will be heard where the editing has been done. Further it is claimed that spectrographic analysis using softwares like audacity soundforge, etc. editing can be confirmed as the graph will show peculiar breaks.
It has been claimed by some that after editing if the file format is converted several times and than it is converted back to its original format and attributes, the editing becomes impossible to detect. I want to know how far this is true? Is there any software which can automatically detect editing without the use of critical listening and manually searching for edits in the spectrograph.
I will be grateful If anyone can throw light on this issue
Thanks in advance
Regards
If someone is an expert with the sowftares named or an forsenic expert he surely would be to tell with confidence if it's altered or not
 

Hiten

Well-Known Member
Joined
Oct 17, 2008
Messages
3,069
Points
113
Location
Kalyan
I want to know how far this is true? Is there any software which can automatically detect editing without the use of critical listening and manually searching for edits in the spectrograph.
I will be grateful If anyone can throw light on this issue
Thanks in advance
Regards
Any editing in the audio format can be detected by software, for example Adobe Audition Frequency Spectrum Analyser. One has to compare the 'original' and the 'edited' file. It shows graphical nature of differences right from frequency to amplitude on timescale. Adobe Audition latest version has come out with graphical editing of this frequency spectrum image where we can manipulate things easily like photo editing software. Somewhere in the forum I had uploaded cleaned 78 recordings. They are amazingly wonderful software.
Good day.
Regards.
 

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
18
Location
india
Any editing in the audio format can be detected by software, for example Adobe Audition Frequency Spectrum Analyser. One has to compare the 'original' and the 'edited' file. It shows graphical nature of differences right from frequency to amplitude on timescale. Adobe Audition latest version has come out with graphical editing of this frequency spectrum image where we can manipulate things easily like photo editing software. Somewhere in the forum I had uploaded cleaned 78 recordings. They are amazingly wonderful software.
Good day.
Regards.
Thank you but there is only one file the original file is not available. So the file available could be said to be the original file. Is there a way the software can flag the specific locations where edits have been made? As I have mentioned in my post is it possible to hide the edits by conversions and reconversions to the extent that the finally the edits made cannot be detected visually through spectrograph or critical listening? Will Adobe Audition bring out the edits despite these multiple conversions?
Thanks
 

Hiten

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Messages
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Location
Kalyan
No then it will not be possible as we don't have reference. For frequency response changes will definitely not be detectable. However if there is distinct editing like cutting and adding there is very low chance possibility of detecting. Which will require not only software but an expert who can decipher. Converting to different format and restoring to original format will also make changes to the WHOLE original file and will probably make it more difficult. Also tell what do you mean by editing ? What were the changes made specifically ?
 

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
18
Location
india
Thank you Hiten. The matter relates to a close friend of mine, its a divorce case and the audio clip has been submitted by the other party as evidence. We both are non technical persons. Since I am a member of this great forum and there are such great technical people, like you, on this forum who are ever ready to help, I took the initiative to put a query here. The editing means additions/deletions. My friend believes that there are certain words which are not there in the audio clip which he had said and further there are some words which appear, but not to have been said at that particular time which change the context altogether. Consultation with forensic experts revealed that if the file is converted and reconverted 5 to 6 times and than it is brought back to its original format than it is next to impossible to detect the edits, hence this post. Although there are some very glaring digital anamolies but the experts say that they are digital discrepencies hence would not stand in the court. Frankly neither I nor my friend understand these discrepencies and their importance. Nevertheless if you can suggest something than please do.
Thanks & Regards
 

cha_indian

Active Member
Joined
Dec 14, 2007
Messages
449
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28
Location
Hyderabad/Chennai, India
Thank you Hiten. The matter relates to a close friend of mine, its a divorce case and the audio clip has been submitted by the other party as evidence. We both are non technical persons. Since I am a member of this great forum and there are such great technical people, like you, on this forum who are ever ready to help, I took the initiative to put a query here. The editing means additions/deletions. My friend believes that there are certain words which are not there in the audio clip which he had said and further there are some words which appear, but not to have been said at that particular time which change the context altogether. Consultation with forensic experts revealed that if the file is converted and reconverted 5 to 6 times and than it is brought back to its original format than it is next to impossible to detect the edits, hence this post. Although there are some very glaring digital anamolies but the experts say that they are digital discrepencies hence would not stand in the court. Frankly neither I nor my friend understand these discrepencies and their importance. Nevertheless if you can suggest something than please do.
Thanks & Regards
I think most people here are audiophiles in the sense that they enjoy music on high end systems.. What you need is a person experienced in forensics which is a altogether a different subject. Since this is a court case, I suggest you get in touch with police's forensic department or any other method.
 

avr

Member
Joined
Feb 27, 2013
Messages
131
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18
Location
india
I think most people here are audiophiles in the sense that they enjoy music on high end systems.. What you need is a person experienced in forensics which is a altogether a different subject. Since this is a court case, I suggest you get in touch with police's forensic department or any other method.
Thank you for your reply.
Rgds
 

captrajesh

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AFAIK, audio clips are not admissible as legal evidence. Correct me if I'm wrong.
 

Sushant Sharma

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Joined
Jul 19, 2016
Messages
538
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93
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Himachal Pradesh
https://blog.ipleaders.in/voice-recording-evidence/

Here is a detailed article by an Indian author talking in detail about Audio/ Voice recordings being admissible in Indian Courts as Evidence under IT Act and Indian Evidence Act. However the burden of proof to prove such an audio clip/conversation is quite strict. The Party leading such evidence needs to satisfy beyond doubt the genuineness of such evidence. Hope it helps.
 

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
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Location
india
I think they are Capt. as corroborative evidence. Thanks Sushant but the strict part although applicable in writing but not followed in practice, atleast not in lower courts.
Rgds.
 
Last edited:

Sushant Sharma

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538
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I think they are Capt. as corroborative evidence. Thanks Sushant but the strict part although applicable in writing but not followed in practice, atleast not in lower courts.
Rgds.
AVR, just from a brief research and decided cases I see that "auditory analysis" "waveform and spectographic analysis of audio and video files to find any alterations " (the words in inverted commas are from a decided case in India) are methods that FSL do use in Court cases in India to decipher genuiness of an electronic record .

I suggest and as said by cha_Indian before me that you find out from your lawyer or police or An FSL Lab how the issue of alteration in an audio recording is specifically looked into by them upon order of a court. I guess this is exactly what you were looking to find from this forum but I also think you will find more relevant and credible answer from the horses mouth.
 

avr

Member
Joined
Feb 27, 2013
Messages
131
Points
18
Location
india
Thanks sushant appreciated. The Govt. labs , as far as I have researched, use outdated methods for voice matching. They do not calculate probability in their tests and neither mention it in their report. Well what I am still trying to understand is whether conversion and reconversion of an audio file multiple times renders it insusceptible to detection for any tampering, as was told to me by an expert.
Rgds
 
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