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ANALYSIS ON THE VIDEO CLIP PUBLISHED BY CHANNEL-4,UK

ANALYSIS ON THE VIDEO CLIP PUBLISHED BY CHANNEL-4,UK. Comparison of video and audio frames of the first gunfire of the video clip. First Gunfire. Corresponding sound waveform has a delay of 296 milliseconds. Sound waveform of Gunshot starts here. 296 ms.

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ANALYSIS ON THE VIDEO CLIP PUBLISHED BY CHANNEL-4,UK

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  1. ANALYSIS ON THE VIDEO CLIP PUBLISHED BY CHANNEL-4,UK

  2. Comparison of video and audio frames of the first gunfire of the video clip

  3. First Gunfire

  4. Corresponding sound waveform has a delay of 296 milliseconds Sound waveform of Gunshot starts here 296 ms The Gun fires here according to the video

  5. ANALYSIS OF THE TIME DIFFERENCES BETWEEN THE VIDEO AND AUDIO FRAMES • The video image of the gun shot occur at the 05.544 second time line in the data stream • The corresponding audio waveform for the above video image starts at the 05.840 second time line in the data stream • Thus; the time delay between the time lines of the image and audio frames = 05.840-05.544 = 0.296 seconds

  6. POSSIBLE REASONS FOR THE TIME DELAY • Technical conditions of the camera used, weather conditions or other environmental effects. • Video recording has been done far away from the gun fire Therefore the video image is transmitted as a light signal which travels faster than its respective audio signal to the camera lens • Audio stream has been added later and not properly synchronized

  7. Possibility One: Is it Natural ?–Field Experiment A field experiment was done by Sri Lanka Army analysts in a similar environment as seen in the published video clip. • In the field experiment • A single T-56 round was fired in an open area • The video and audio information was recorded using a mobile-phone camera • The distance between firer and camera (as seen in the above image frames) was about 4 meters

  8. Possibility One: Observations; Field Experiment • The time line of the image lags the time line of the start of the audio data Time advance Sound of the gunshot Gun fires on video The sound records before the corresponding video images appear in the video stream

  9. Possibility One: Analysis and Results: Field Experiment • The sound records before the corresponding video images in the equipment. • As technically audio data is sampled at a much higher rate (8000 samples/s) than the corresponding video data (7.58 frames-samples-per second) • However, in the published video clip the audio data of the gunshot is recorded after the corresponding video image/data Therefore the published video clip recording has not been done under a normal recording condition

  10. Possibility Two: Video recording has been done far away from the gun fire?-Analysis, Results • Sound waves travel at 346 meters per second. • The distance the sound emanating from the firing the gun, travels during the observed delay of the published video clip of 0.296 seconds to reach the recording device = Speed of sound X Time • = 346 x 0.296 • = 102.4 meters Sound Propagates at 346 m/s Distance should be 102 metres As per the calculation of the observed time delay, the incident had been recorded from 102 meters away . RESULT: This is NOT possible with a mobile-phone camera

  11. Possibility Three: Audio stream has been added later and not properly synchronized? • The only plausible explanation on the observed phenomenon is that the video clip is “a doctored video clip”–i.e image taken from a particular source to which the audio data has dubbed later .

  12. Thank you

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