Questions tagged [compression]

The use of identifying patterns in video to reduce the required data rate required to create a video stream.

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28 views

h264 compression keeps same number of frames?

I'm trying to understand how h.264 compression works. So far I have clear what I, P, and B frames are and how are they used. But I'm unsure of is if after this process the number of original input ...
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26 views

Efficiently compressing a looping video with h264

I have a video that is initially 19 frames long and lasts for about 0.5 seconds, it's 432kB. I've looped it over three minutes and the resulting file is quite large (200MB). Using FFMPEG is there a ...
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1answer
11 views

What is a cost effective app to resize, crop & save a MOV file to a reduced size?

I am planning to buy an HD animation which is over 500Meg in size. I need to resize, crop and reduce the file size to about 10Meg. I prefer not to deal with Adobe Media Encoder or something like ...
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1answer
34 views

Camera flash produces unwanted artifacts on the video

During frame by frame watching of some video taken via Instagram app one noticed strange unwanted artifacts on the video caused by camera flash. Please, consider below several sample image frames ...
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1answer
19 views

error editing a long video using VirtualDub2

I have several long video files that I need to edit (remove some initial parts, breaks and dead moments) and I always got errors when I try to save / export the edited file in mp4. The pcm_f32le: ...
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27 views

Is there a tool that lets me cut video with frame precision?

I'm able to use Avidemux with enough ease and it's mostly enough for my video need. I can also choose codecs to recompress the video. Unfortunately, it doesn't let me cut video outside the scope of ...
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1answer
48 views

How to prevent frame smoothing (i.e. get really sharp frame images) when making a video with ffmpeg?

I have been digging around here and on the ffmpeg site trying to find some commands to use to generate a movie from a set of images. The command I tried that gives me a video I can watch on my MacBook ...
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13 views

Streaming Compression Math

Using 4:2:2, the data rate and compression are: 4k -- 11.88 Gb/s -- 339.4x HD -- 2.38 Gb/s -- 237.6x Assuming 4:2:0 for both, Netflix and Stadia use the same compression for HD. To use the same ...
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1answer
35 views

Why both videos are of same file size?

I am using ProMovie Recorder to record high quality videos using iPhone X, and I noticed a weird thing today. Here's what I did: I recorded a 4K 60fps video for 6 seconds (HEVC encoding). I recorded ...
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1answer
15 views

Software that captures and compresses simultaneously

I'm trying to find open-source software that compresses video captured from a webcam automatically. I'm thinking of automatically compressing like in post-production. For example, compressing the file ...
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1answer
183 views

Export Frames of 10 BPC Video File with ffmpeg

I have several hundred 1080p 59.94fps 10-bit-per-channel (bpc) AVC-Intra Class 100 MXF encoded video files. I would like to extract the frames of this video file and export them to disk in a 16-bit ...
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41 views

How can I change/reduce the bitrate of AVI files using Adobe Premiere Pro CC or other tools?

I'm using Eprime and Experiment Builder which requires files in AVI format (AVI-XVid). The files are quite small already (various 2 second clips under 1mb), but are still too large which crash the ...
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2answers
118 views

What's the difference between “visually lossless” and real lossless and what does this mean for future encodes?

In FFmpeg's H.264 Video Encoding Guide we are told: Tip: If you're looking for an output that is roughly "visually lossless" but not technically lossless, use a -crf value of around 17 or 18 (you'...
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30 views

Blurring based on colour (to help compression)

I am taking video of rowers on a river and stabilise the video afterwards using ffmpeg. Similar to Video compression- how to prioritize one area over another? I'd like to optimise the compression. The ...
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58 views

Some H.264 videos that I have seem to have excessive bitrate, is there a way to determine/find their recommended bitrate?

So I have some videos that are Full HD, h264 but they have over 30M bitrate at 30 FPS, they are SDR and their quality is not very impressive so it seems excessive and unnatural for such unimpressive ...
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1answer
62 views

Recompressing 1080p h264 collection to HEVC - Target Bitrate For Minimal Loss

My understanding is that HEVC (aka h265) can provide roughly the same video quality as h264 in roughly half the space, for 1080p+ footage. I have a large collection that I would like to re-encode to ...
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1answer
122 views

What happens when you use a specific CRF value on a already encoded x264 video?

If there is a h.264 video, and I use -crf 17 I sometimes I get a lower bitrate, but the weird thing is - most of the time get a higher ones. I am trying to get this setting because I think some ...
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1answer
223 views

ffmpeg clear video cache

I am running a compression script to compress my large AVI files to small mp4 files. The script look like this #!/bin/bash FILEPATH="$1" COMPRESSIONPATH="$2" ffmpeg -i $FILEPATH -vcodec h264 -acodec ...
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Before I throw away these massive uncompressed VHS digitizations, what kind of post processing can I do to improve them?

An uncompressed digitized VHS tape is like 60 gigs. Obviously way too big. I can compress it down using H.265 and get basically the same quality. But before I do that, is there any production ...
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62 views

ffmpeg video compression : Compress captured video being before saving to file

Is there a way one can compress captured video input before saving to file? I have raspberry pi that I am using to record youtube videos. 1-2 min video takes over a Gb of space. I cant compress the ...
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1answer
35 views

What happens when a compressed video is played back?

I've been reading up on video compression. I understand that 'raw' media file sizes are to big for practical usage so they have to be compressed, but I'm wondering what happens when the video is being ...
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1answer
61 views

MJPEG Streaming

in https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Video/pktvideoaag.html it says: Another type of video compression is MJPEG … the resulting video stream is larger but the packet sizes ...
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1answer
35 views

mp4 to wmv AND file compression

I have a mp4 from a video created in iMovie 10. The original output is about 1.5 GB. I uploaded it to youtube to use their compression and re-downloaded. I now have an mp4 at 236mb. I need to ...
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2answers
934 views

Using ffmpeg to add height (as black bars) to video file without quality loss

I have a file of resolution 3840x1632, but my TV stretches the picture vertically to fill up all 2160 pixels of height. Is it possible to use ffmpeg to add blank / black height, while preserving the ...
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2answers
109 views

Grime-like blocking compression artifacts on the decompressed video (H.264)

During watching H.264 compressed videos one faced several times with an artifacts. Example 1: Example 2: Wikipedia's article [1] tells that the typical reason is «Data errors in the compressed bit-...
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21 views

Why does people seem transparent in this video

People seem transparent in that video. What does explain that? I posted on the Physics community, believing that it was related to some optical effect. But I've been told that it may be related to ...
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1answer
45 views

Video cam with poor compression ratio (H.264 produces videos at 2.9MB/sec)

I just purchased a cheap dashboard video-camera that is advertised to have a H.264 codec inside. However, after the first video test I have seen that a 43sec movie takes 123MB! How is this possible. I ...
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0answers
8 views

Why does motion compensation need a decoder?

I know that motion compensation is the process of using the motion estimaton MV information and then compensating it to describe only the differences between reference frame and the motion estimation ...
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1answer
90 views

Different rate distortion curves for two videos encoded with same parameters in FFMPEG

I encoded two videos (ParkJoy and Sintel) in FFMPEG by H.264 with same parameters (GOP size, QP, frame rate, resolution etc.) and obtained rate-distortion plots (mean PSNR of Y channel vs bitrate). I ...
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2answers
1k views

How do I avoid objects having flickering edges when I encode a screen recording to mp4 using x264 and ffmpeg?

The Goal I'm creating short tutorials by recording my screen (720p30fps). The content is just a recording of using some desktop software - so mouse moving and opening dialogs, typing, drawing shapes, ...
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72 views

Lossless and lossy compression techniques

Are MPEG and H.264 Lossless?? I need a brief explanation about lossy and lossles... And which compression technique is generally using in CCTV Surveillance applications of video??
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93 views

Optimizing HTML5 video for best quality

I have a 3 minute video I'd like to embed on a web page. The problem is that despite best efforts, the file size of the video ends up being over 30 mb. I would like the size to be near 10 mb. I have ...
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1answer
344 views

Are JPEG compression and H.264 intraframe compression the same process?

I was looking at how JPEG compression works, and to me it seems to be really similar to what H.264 (and other video codecs) does with its intraframe prediction step. In both algorithms the image ...
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1answer
62 views

Does increasing the framerate while not changing the content affects compression quality?

This question has no practical importance for a regular video production pipeline, but nonetheless it's something I find fascinating because it would imply video codecs use temporal sub-sampling ...
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1answer
254 views

AVI Capture in VirtualDub: MP3 Compression

I would like to capture my old VHS tapes to my HDD. I already was successful installing the xvid codec which gives me an acceptable video compression. But somehow I am not able to set audio ...
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1answer
18 views

mp4 file expands wildly when shortening clip

noob here, I took a video of myself for a wedding greeting with my phone (LG Nexus 5 [Android]) sitting (the phone that is) in a windshield suction holder. The video is 3'42" long and when downloaded ...
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1answer
342 views

mov to mp4 conversion produces grainy results

I am using handbrake to compress 250mb of 3d animation stored in .mov. This is how the mov looks: The compressed version has some artifacts. Like it doesn't have enough shades of grey: How can I ...
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1answer
473 views

Reencoding H.264 to H.264 made it 40% larger

I've got some livestreamed footage (encoded with constant bitrate), and I've been trying to reduce the file size for long-term storage. I figured that since encoding speed is no longer a constraint ...
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92 views

Best possible quality setting for screen recording (not games) and web presentation

Screen videos have text and simple geometric shapes, which need to stay sharp, detailed and crispy. The color should also remain untouched. With screen grabs, I want e.g. IBM blue to show as IBM blue ...
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1answer
147 views

Please Explain the Codecs in my Example [closed]

Can someone explain what's happening in my project? Please use as much detail as possible, I just want to learn, thanks. I have an Apache web server. It contains many videos (.mp4 .mkv which are ?...
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1answer
70 views

Archiving raw video

I am trying to organize the videos on my external harddrive. I have a lot of home video shot with a hand held camera, and now I am using a GoPro 4 camera that I record 4K video with. It consumes a lot ...
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1answer
769 views

Largest input image size when encoding a video?

I got a bunch of really large 16 bit videos, approaching 65535×65535 pixels in size. These are essentially high quality timelapse panoramas. I want to convert them to a 7680×4320 movie (8K UHD, 8 bit)....
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2answers
84 views

Chroma subsampling notation - rules

Are there some simple arithmetical relations (rules, properties) between numbers in x:y:z chroma subsampling notation?
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1answer
52 views

Video compression- how to prioritize one area over another?

I'm not sure if what I'm asking is possible, but here's the situation. I have a video I have made for distribution on the Internet (YouTube, Vimeo, etc.) The video clip is a composite of the ...
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1answer
867 views

How does the h.264 encoder determine where to put i-frames?

I'm reading a bit on I-frames and their counterparts, P-frames and B-frames. I understand the usage. I-frames are the key to the compression and following P and B-frames can use the data in I-frames ...
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2answers
2k views

What deinterlacing filter should I use to encode/compress a PAL MPEG-2 576i 25fps raw file?

I have a PAL MPEG-2 576i 25fps raw capture (presumably either straight from satellite or a DVD recorder) that I would like to encode to AVC. I'd like to deinterlace the file during compression with ...
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1answer
45 views

Prediction and Motion Estimation

As far as I understand, the motion estimation is a process, where when we have two frames t and t+1 we search for the blocks/pixels that changed position and then encode that change with a motion ...
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4answers
747 views

Compressing of DSLR video

I m recording full HD video in 1080p /30p format with my Nikon D5200 but i find the size of video is to high i.e. 10 GB for an hour. Now i want to compress it to lesser size in the range of 1-2 GB ...
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3answers
756 views

Is there a way to improve quality for videos with snow/confetti/LCD in background?

The effect I'm referring to: Essentially, the snow/confetti in the shot means lots of motion, hence a lot of the available bitrate is taken up by it, thereby ...
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0answers
124 views

If I limit the color spectrum of a video, will it compress to a smaller file size?

I know that in exporting images, if I use an indexed color format when I save (such as GIF or PNG with indexed color mode), I can dramatically reduce the file size of the resulting export. My ...