5 votes

What is difference between the terms bit rate,baud rate and data rate?

Bit rate and data rate are somewhat ambiguous, and their exact definitions vary from one field or application to another. Bit rate is often used to measure the information rate, since information is ...
MBaz's user avatar
  • 15.3k
5 votes
Accepted

When a face collapses into a swirling black hole on a video conference call like this is it due to some advanced AI-based error-correction gone wrong?

This looks like what pretty "classical" video compression does when facing severe data loss – notice the very MPEG-typical square blocks, and how some of the probably more changing blocks ...
Marcus Müller's user avatar
4 votes
Accepted

Can deep learning be applied to video compression?

[EDIT: addition of a March 2017 preprint] Deep learning already has many applications in video, like enhancement (Deep Convolutional Neural Network for Decompressed Video Enhancement) or semantic ...
Laurent Duval's user avatar
4 votes
Accepted

Identifying license plate number of a thief's car from a video

Averaging may not be the best option, due to motion compensation in video frames: one number (say $8$) may be extrapolated for another (say $3$) on a different JPEG block. It might be interesting to ...
Laurent Duval's user avatar
3 votes

My fft gives always gives the correct frequency or double the correct frequency

The 'beat' that you are looking for is a periodic signal but NOT a sine wave. So it can be represented as a sum of sine waves: the fundamental and multiples of it (harmonics). $$ x[t] = \sum_{n=0}^{P-...
Hilmar's user avatar
  • 44.7k
3 votes

Difference between frame and image?

Frame is the element in the time index of a video. For 2D videos, each frame is an image. Frame Rate is just the sampling frequency of the time index of the video.
Royi's user avatar
  • 19.6k
2 votes
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How to sync audio and video signals in MATLAB?

Thanks to helpful comments from @MBaz, I managed to come up with a solution: we can associate multiple audio samples with a single frame using the VideoFileWriter object. This fact and use-case is ...
AruniRC's user avatar
  • 180
2 votes
Accepted

How Can an Object Move by Less Than a Pixel Between Two Consecutive Frames?

The frame is 2D Grid which samples the continuous world in Discrete way. Leave alone video for a second. Let's talk about taking a photo of a white paper laid on a black surface. The photo is taken ...
Royi's user avatar
  • 19.6k
2 votes

Video stitching for static scene (infinite loop video)

Lets assume your camera axis has polar and azimuthal angles and you want to align your frames only regarding the azimuthal angle and set the polar angle free. First you have to find the geometric ...
Mohammad M's user avatar
  • 1,327
2 votes

Identifying license plate number of a thief's car from a video

There is a company named Signalscape who has a line of products called StarWitness (http://www.starwitnessinfo.com/) that do forensic video analysis that are available to law enforcement agencies (...
mikefo's user avatar
  • 21
2 votes

RF demodulation for dummies

A good answer might constitute a few chapters in a good DSP text, making this question overly broad. So I'll sketch an over-simplified skeleton, where you will need to seek a decent rationale ...
hotpaw2's user avatar
  • 35.3k
2 votes

Interpolation of audio for new frames

When upsampling the number video frames to allow playing a video in slow motion, rather than for a frame rate increase for smoothness, you will likely need to modify the audio using a time-pitch ...
hotpaw2's user avatar
  • 35.3k
2 votes

How Can I Remove Flickering Background in a Video?

I've used in the past Julie Delon's flickering removal (pdf) approach which is based on midway image equalization. It's not hard to implement, and the parameters are easy enough to tune. Since it ...
sansuiso's user avatar
  • 3,937
2 votes
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How Can I Remove Flickering Background in a Video?

For those classic Video Processing operations there is nothing better than the Plug In's of AviSynth. Specifically for De Flickering look at: LMFlicker. ReduceFlicker. DeFlicker. The source code of ...
Royi's user avatar
  • 19.6k
2 votes

Is it possible to calculate/estimate the storage space a certain duration of .mp4 video files will take up?

No. The MPEG4 video codec allows for a large ranges (easily a dynamic range of 50 for "useful" quality) of compression ratios for the same raw video material. The same applies to audio compressors. ...
Marcus Müller's user avatar
2 votes

2D to 3D view conversion

It seems to be at a stadium which uses 12 cameras and Replay-Technologies special signal processing called FreeD: https://www.youtube.com/watch?v=N1kgt2VDjdM The image you show seems to use 2-3 ...
bandybabboon's user avatar
2 votes

Difference H264 and H265 algorithms

The high-level picture is that h.265 allows lower bandwidth at the same visual quality (or more visual quality at the same bandwidth). It achieves this by using more advanced techniques that require ...
Knut Inge's user avatar
  • 3,394
2 votes
Accepted

What's the purpose of dividing the light and combining back in TV Cameras?

This is the process of using dichroic prisms for color separation in high end camcorders and digital cameras. The other approach used is with color filters directly on a single CCD photosensor in a ...
Dan Boschen's user avatar
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1 vote
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How to use optical character recognition program to read coins?

Without seeing the coins it's not easy to give a unique solution. A possibility would be: Use the Hough transform to detect circles (the coin). Then do some open/close operations to get blocks of text,...
Filipe Pinto's user avatar
1 vote

How to recognize for small video sequence with a large sequence?

The most intuitive approach here would simply be taking every pixel's color values, and finding peaks in the individual pixels' reference video/short video cross correlation function. That's basically ...
Marcus Müller's user avatar
1 vote

temporal high-pass filtering to approximate phase derivative

I am not familiar with the algorithm you have proposed, but I believe I can answer the question you asked. Once you have computed the DFT of your image, what you get is a 2D array of complex number. ...
Pier-Yves Lessard's user avatar
1 vote
Accepted

Video processing to detect a logo in frames

If you know where the logo is then you can detect its presence, fairly quickly, with cross-correlation...with a little bit more work. Detecting the presence of "things" using cross-correlation is a ...
A_A's user avatar
  • 10.7k
1 vote

Does the cv2.waitKey argument determine the frame-rate while capturing a video?

It does not determine the framerate, but it has an influence on the framerate. The first caveat is that although you're only waiting 1ms between frames, the program has other work to do in order to ...
Apollys supports Monica's user avatar
1 vote

Measure the amount of drift in video and audio frames

the two cameras are not genlocked and as a result I expect there to be some drifting between the frames of the two video/audio signals. Drifting would imply that ...
A_A's user avatar
  • 10.7k
1 vote

Video stabilization using Lucas-Kanade method

For video stabilization, you need to estimate motion vector with respect to a reference frame $F_{reference}$ (which let's assume it to be the first frame). Then your motion model should be determined,...
MimSaad's user avatar
  • 1,976
1 vote

Can deep learning be applied to video compression?

Well video compression is essentially changing the representation of the video into an intermediate one, such that this representation could be used to recover the original video to the best possible ...
Tolga Birdal's user avatar
  • 5,465
1 vote

Video compression - why not just sending the changed parts?

Video codecs tries to find apparent movement (akin to optical flow) first. Bits have to be allocated to describe that motion. Then the residual is coded using a lossy transform/quantazation that tends ...
Knut Inge's user avatar
  • 3,394
1 vote
Accepted

Video compression - why not just sending the changed parts?

You could do that, in theory, if you knew "what are the parts" (or objects) frame-to-frame in a video. But: objects move, change scale, rotate, have color changes, they even can be occluded. the ...
Laurent Duval's user avatar
1 vote

Pixel Wise Write into a Video File in MATLAB

I assume your matrix is 3D where the first 2 dimensions are Width and Height and the third is time (Gray Scale Video). If you can write your processing as a Filter you can use MATLAB's ...
Royi's user avatar
  • 19.6k
1 vote

How to Reduce Noise in a Video Stream?

Usually, Salt and Pepper Noise is done using Median Filter. There are variations of the Non Local Means to deal with Salt and Pepper but it might be overkill so I'd start with the above. The tricky ...
Royi's user avatar
  • 19.6k

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