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Questions tagged [video-compression]

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5
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0answers
42 views

Converting very short “motionless” video frames to single, better-resolved, images

I made a mistake with my newly bought compact camera, before a trip to Japan. Instead of taking single pictures, I ended up with a few short "MP4" video files (1 second, 2-3 frames). I could "easily ...
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0answers
75 views

FFmpeg Block Motion Compensation Only

is there a way to just perform block motion compensation using ffmpeg command line (i.e. no addition of residual encodings). I want to compare the quality of the video frames produced using various ...
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0answers
85 views

Can lossy video encoding result in identical adjacent frames?

When using lossy encoding can similar adjacent video frames become merged or even identical? For example, if frames A, B and <...
0
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1answer
34 views

How we can show that 2 correlated videos are similar?

Can I tell that different versions of the same video are correlated to each other? and if so, how can I show this correlation? for example, high-quality and poor-quality versions of the same video. ...
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0answers
41 views

Is signal processing used in block matching algorithms

I'm working on a custom video codec which uses the standard mean squared error to find blocks. As explained by this youtube video you choose a search area size to find a block in. Each pixel of the ...
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0answers
39 views

What is wrong with my 3D DCT quantization?

I'm implementing 3D DCT quantization as in Quantization of 3D-DCT Coefficients and Scan Order for Video Compression (sorry about the paywall). They propose the following equation for generating the ...
0
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0answers
80 views

What is the application of Walsh-Hadamard transform in interger discrete cosine transform?

I'm trying to understand and implement 3D DCT for video compression. An important part of that is the quantization of the coefficients and efficient implementation of the 3D DCT. So far I've been ...
0
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0answers
13 views

Vector based video coding, could it match the latest hybrid coders?

I could not find any image/video/media coding stackexchange so I thought that maybe this one would be the best fit. It seems to me that the state of the art in video coding is constantly being pushed ...
0
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1answer
219 views

Compression ratio for 4x4 block

Say I have the following 4x4 block: [ 120 121 125 119 120 120 118 117 122 121 117 118 122 122 120 120] If this block is intra coded the ...
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2answers
99 views

Fast method to decompress huffman and arithmetic encoded data

By nature, when decompressing huffman (and I assume also Arithmetic encoded data) we have to read it in bit by bit and then see how it traverses a huffman code tree that has the actual symbol value at ...
0
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2answers
90 views

Video compression - why not just sending the changed parts?

I'm trying to understand how video compression through dense optical flow works (I'm a newbie with video compression). I easily understood what optical flow is, the thing I can't understand is why a ...
0
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1answer
332 views

How to reduce noise in a video stream?

I've been using Open Broadcaster to stream the infrared HDMI output from a 4K Sony video camera. It works pretty well, but one thing that I'm finding a little annoying for image analysis is the ...
5
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3answers
6k views

Can deep learning be applied to video compression?

H.265 is based on incremental gains over time. The paradigms have largely remained the same. What are the odds of deep learning providing huge performance gains? Here is the main metric: Perceptual ...
0
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1answer
388 views

Extract the count of particular macro block types(I, P and S) from the frames in the video

How can I extract the count of particular macro block types(I, P and S) from the frames in the video (H.264 and MP4)? Also, I would like to extract the prediction residual of each of the P and B ...
1
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1answer
2k views

Calculate sum of absolute difference per pixel

I am trying to implement a research paper just to verify my results. I have shared the code (written by me) and the description of the process given in the research paper. Unfortunately my results are ...
0
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1answer
384 views

Extracting DCT coefficients from H.264/AVC bitstream

Is it possible to extract DCT coefficients from H.264/AVC bitstream without doing a full-decoding of the video? There are a lot of papers on compressed domain video processing which are based on the ...
3
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2answers
83 views

Why are vector quantizers not used in video codecs?

Using a vector quantizer (VQ), groups of image samples (or motion compensated and/or transformed data) can be quantized as vectors. I'm curious about why VQs are not preferred in the modern, highly ...
0
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1answer
358 views

I B P video frame reordering

I am studying H264 video these days. I know video encoder will do frame reorder for GOP with B pictures.I am not sure if my understand is correct! GOP input to encoder (it's raw data but I just map ...
2
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2answers
4k views

Extracting motion vectors from H.264 bitstream

I'm looking for an open-source tool/code or some guidance to extract the motion vectors (MVs) of a H.264 encoded bit sequence. I'm already aware that motion vectors can be visualized using ffmpeg with ...
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0answers
143 views

Difference between video mosaicing and video stitching

What is the difference between video mosaicing and video stitching ,is this both are similar or is there any methodology difference?
1
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1answer
395 views

HEVC Deblocking filter algorithm

I'm doing research on block noise caused by video compression (especially in newer codecs) and I've read the IEEE article about the HEVC deblocking filter (here). However, when reading the algorithm ...
3
votes
1answer
1k views

Difference Between monocular video and stereo video?

What is the difference between monocular video and stereo video ,as i am studying about motion tracking i need to know the meaning of these two things.
1
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2answers
73 views

Noise modeling and reduction in Video when we have just noisy video

We would like to send a video (sequence of images), we have limit bandwidth. If there is a lot of noise, the required bandwidth (bitrate) is needed to send the video+noise becomes high that is not ...
1
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1answer
141 views

How are video thumbnails chosen?

Of the thousands to millions of frames that a video might have, how is a particular representative frame chosen to be the thumbnail?
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0answers
52 views

Detecting inset images/videos from a video

I want to detect multiple rectangles in a video, each of which features a different content, but running simultaneously. This is typically seen during debates on news channels. For example, in the ...
3
votes
1answer
9k views

What does the 420 means in YUV420?

I'm not sure if is the correct location for ask this question. If not please info me the correct StackExchange site. As this wikipedia page show, there is one YUV format of image as YUV420 and YUV411. ...
12
votes
1answer
4k views

Relationship between DCT and PCA

I have a basic implementation knowledge of the 2D 8x8 DCT used in image & video compression. Whilst reading about Principle Component Analysis, I can see a lot of similarity, albeit PCA is clearly ...
4
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2answers
299 views

Exam Question - end-to-end delay from video capture to video playout

Hi I'm preparing for my exam tomorrow and I've come across a 17 Mark question which seems trivially easy, so I think I'm missing a key point giving the rest of this exam is fairly difficult. The ...
3
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2answers
286 views

Video Compression - When would an average of the previous and next I or P frame be useful

I'm doing practice exam questions for my multimedia systems exam one tuesday and a topic which seems to come up frequently is the appropriate use of encoding B-frames based on: 1) the previous I or ...
5
votes
2answers
555 views

Extracting top & bottom fields from a YUV 4:2:0 Frame

I am wondering what would be the right approach to extract top and bottom fields from a YUV 4:2:0 frame. In the YUV 4:2:0 representation, Luma and Chroma samples are located as shown below: Y Y Y Y ...
6
votes
2answers
2k views

Low MIPS Video Encoder

I am looking for a low MIPS, low compression video encoder. This is for a 10fps, VGA type quality compression. What are my options? I need to be able to do this compression using a 150MHz ARM M4 CPU ...
7
votes
1answer
433 views

Extremely computationally intensive image/video compression schemes which offer better compression than industry standard JPEG/H.264

I am trying to search for image/video compression schemes which offer superior compression performance (holding image quality as constant) when compared to widely adopted industry standards (i.e. JPEG/...
15
votes
3answers
9k views

How do the motion vectors work in predictive coding for MPEG?

In MPEG, there is a process where an image is broken up into macroblocks and a motion vector is computed for each of those macro blocks. You then transmit these vectors, along with the prediction ...