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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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1answer
31 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
26 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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9 views

WebEx Recording converted to a standard, high-quality file, with editing

I want to create a video file from a WebEx recording. I want that file to be small but high quality and playable on video players such as VLC Video Player. I want to edit the file (suppress some ...
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1answer
11 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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1answer
47 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
13 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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20 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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17 views

FFmpeg lossless RGB->YCgCo->RGB looking faded

I'm experimenting with using video codecs for compressing still images. I have 24 bit PNGs as the source files and everything is fine using rgb video codecs but I'm having trouble getting yuv codecs ...
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1answer
25 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
7 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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39 views

List of light and lossless codecs supporting alpha channel

first question ever. In my app I use ffmpeg to overlay half-transparent graphics (png) on rushes. Now I want to overlay videos like this [one][1] with the following requirements : lossless light (...
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1answer
32 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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13 views

Codec optimised for changes in small part of the frame

Which modern codec(s) are best optimised for a video file that contains constant changes but only in a very small portion of the frame? I'm thinking like a desktop background with the mouse cursor ...
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2answers
384 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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1answer
22 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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22 views

What encoder settings does youtube use to compress videos?

After I render files from Premiere (or Vegas Pro), and upload to YT, i see that highest quality video on YT (which i download) is 8-10 times smaller than original filesize, and what's more, visually ...
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17 views

Recompressing H.264 footage without lossing quality

I often use NVIDIA Shadowplay to record, and the footage is often always very inefficiently compressed, being about 40Mbps and 5 minutes long, when in reality I only need it to be 1 minute and I ...
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0answers
66 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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0answers
16 views

Variable Frame Rate recording - principle of operation

You all know the problem: the video straight from your new DJI drone looks brilliant played straight from the original MP4. Then you want to edit it, say in iMovie or Premier Pro and the result is ...
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1answer
46 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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0answers
20 views

Is there any way to force Avid to export a video containing compressed audio (mp2)?

I have been editing a video inwhich I had downloaded the footage directly from iCloud in the hopes of it being uncompressed. The entire video is finished, but I couldn’t export so I realized that it ...
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1answer
32 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
137 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
13 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
125 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
198 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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0answers
44 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
59 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
57 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
389 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
59 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
45 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
441 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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119 views

My .avi files created with ffmpeg are bigger than I want them to be

I'm using ffmpeg to covert .mp4 (x264) Image Size: 992x720 to .avi (DivX). The original mp4 file is 845MB and my .avi file is 2.2GB. What can I do to make it smaller in size except increasing -qscale:...
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2answers
874 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
40 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
446 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
377 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
73 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 ...
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1answer
94 views

How do you dramatically reduce the size of a video while keeping the quality as much as possible?

I'm very surprised how the video i have recorded with my camera are so heavy for small length (i have 4GB for only 20min). I've been trying compression softwares like handbrake, but it doesn't reduce ...
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3answers
114 views

Trading off resolution vs quality

I have some 720p 30FPS H.264 video that I want to downsample for online backup. I want to get to somewhere around 10% to 20% of the existing size, which will evidently require a large sacrifice in ...
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118 views

Modifying FFmpeg command from 2-pass to 3-pass and hardcoding subtitles

I'm working with the following ffmpeg command: ffmpeg -y -i "Original.mov" -pass 1 \ -vf "subtitles=espSbs.srt, scale=1920:1080" \ -b:v 27179k -b:a 128k -f mov /dev/null && \ ffmpeg -i "...
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48 views

Video in h264 format and need to convert to something “playable”

A co-worker gave me footage of a car accident that will exonerate his daughter in h264 format. He needs to convert this into DVD format or anything else that can be played. I own Final Cut Pro, and ...
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1answer
12k views

Big difference in the video file size after the conversion (.mov to .mp4)

After converting from .mov into .mp4, a video file is greatly reduced in size (.mov - 75,2mb .mp4 - 11,9mb) - does this mean that the converted video degraded (loss of color information, or the ...
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1answer
146 views

Converting WMV to MP4

I just joined this community and hope my question is acceptable since it is quite "noob" like. I have a .wmv video file that is 1280x720 and causes windows media player to abort after excessive ...
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3answers
109 views

Best way to trim and save an existing mp4

If I have an existing MP4/H264 video file and I need to trim the start and end, Then save it as an MP4 again, Are there any recommendations on export settings?
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1answer
926 views

Convert 1920x1080 Video to 720x480 With Letterboxing

I'm trying to find the best application on windows to do this HD to SD conversion for a video server which requires files to be exactly 720x480/29.97fps MP4 H.264 to function. I can't find any options ...
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1answer
632 views

Techniques for compressing a slideshow presentation video?

I often do QuickTime screen recordings of slideshow presentations (e.g. Keynote). These videos are 1080p 60fps and mostly text. They can go for minutes at a time with the same exact frame on-screen (...
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1answer
45 views

Compressing a large MP4 file that is on 2.30mins long

I have been sent a video that is only 2.30 mins long. But is a whopping 168mb, unfortunetely this has to be embedded into an app - so I need it as small as possible. I need to get the file size down ...
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0answers
31 views

Motion project has pixelation and artifacting

I just exported an animation I made from Motion 5 and noticed that the edges were pixelated and parts of it had dark fringing Here's the video Any ideas on how to fix it? BTW all shapes were made ...