Questions tagged [encoding]

The process and techniques used when storing moving images, sound, metadata and other streams as a digital file.

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How to re-encode a video file's audio, but leave the video stream with ffmpeg?

Does anyone know how to take a video and re-encode the audio, but just copy the video data using FFMPEG?
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How to H.265 to H.264 without losing quality

I have a MPEG-H Part2/HVEC (H.265) .mkv file (Planar 4:2:0 YUV 10-bit LE). Since my LG PF 1500 beamer does not read H.265 but H.264 I would like to convert it (HVEC -> H.264). I think handbrake is a ...
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How to tell ffmpeg to copy all streams except one audio stream (to encode)?

Input: * One Video * 4 audio streams * Many subtitles * Chapters I want to re-encode one of the audio streams (the first one) and keep everything else as-of (copy). Is it possible to do that in ...
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Errors in converting mp4 to ts with FFmpeg

I was trying to convert a caption-embedded .mp4 file into a .ts file. Only command found after some search was this which uses FFmpeg: ffmpeg -i 1559066401592889640.mp4 -c copy -bsf h264_mp4toannexb ...
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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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How to stop ffmpeg from interlacing when converting from m2ts to mkv

I have a m2ts video file that contains a h264 video stream and an ac3 audio stream. The quality is not the best, but it is okay, but converting it with ffmpeg without any additional options makes the ...
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Is there a mathematical equation to compute the bitrate of a Cisco H.264 stream?

I'm working on adaptive streaming for video. As I'm using a Cisco Open H.264 Encoder, I'm testing multiple configurations for the encoder. A configuration consists in a several of parameters (bps, fps,...
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FFmpeg/Avconv unable to copy subtitles; Unsupported codec?

I've got an mp4 file with these streams (avconv -i file.mp4 or ffmpeg -i file.mp4): Stream #0.0(eng): Audio: aac, 48000 Hz, stereo, fltp, 125 kb/s (default) Stream #0.1(eng): Audio: ac3, 48000 Hz, 5....
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Does HEVC Support 16-Bit RGB Color Format?

I have some 3D Rendered Frames in 16-bit rgba Color Format.... I don't Wanna Lose Any Data... Because I have to Use those in editing.... But With Thousands of Frames in 4K File Size Matters.... So Why ...
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1answer
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Encode a small proxy file with multiple audio streams for editing on Linux

After capturing 2K video in 444p with OBS, I need to transcode it to a low quality proxy version that's still easy to scrub and not a huge file. I capture 3 audio tracks in 32-bit PCM and the image ...
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Is VAAPI the same as hardware encoding?

I don't know if this is the place to ask, it's a bit of a hybrid video/IT/developer question, so my apologies if it is not. I scoured the entire internet and can't find an answer to this question! I'...
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What happens if you uncheck key frame distance in Premiere Pro CS6

The default is 72 which is in frames I suppose. However what happens if I simply uncheck it? Does it work like AVC Intra where key frames doesnt exist and every pixel in every frame is processed like ...
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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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How to encode with x265 cli

I have some raw H.264 10bit videos need to convert to HEVC format, but the encoder only takes some frames (600/170000) to encode, and the video is full of noise. What is the correct way to encode ...
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Encoding Problems in 2019 Premiere, AfterEffects and Media Encoder

I know this question was asked before, and I've read pretty much all of them and I have no solution to this. Until recently, I could render everything just fine but when I am rendering a 2 minute ...
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Can ffmpeg downsample pixels perfectly?

I've tried all the swsflags options and figure the answer is no, but it can't hurt to ask just in case. For example: downsample from 1920x1080 to 960x540, then upsample back to 1080 using the ...
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Good codec for embedded system video decoding

I need to get streaming video working where a source streams video to an embedded platform. This embedded system has an ARM-Cortex-A9 without a GPU or a hardware video decoder. Unfortunately I don't ...
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1answer
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Some MP4s have keyframes on scene changes. Others seem to have random keyframes, or keyframes every X seconds. What causes this discrepancy?

Some MP4s have keyframes on scene changes; others have keyframes seemingly randomly placed, or placed every 5-10 seconds. I prefer the former, both for ease of editing and because, unless I'm ...
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Can't tell if prores4444XQ is any different than prores4444 in ffmpeg 4.1

Using ffmpeg 4.1 and prores_ks codec. I've encoded various clips into 4444 and 4444XQ. All play and look fine but when I try to use -pix_fmt yuv444p16le for 4444XQ I get the warning: Incompatible ...
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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
115 views

Compile FFmpeg example code

I was trying to compile an FFmpeg example code HERE that illustrates how to use filters using it's C APIs. I compiled the code (throuh a universal make). As the usage suggests, I'm doing this: ./...
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What is the proper terminology for a device that can accept IP video streams and output that to RF as used by consumer televisions?

More a terminology question than anything. As described in the headline, I want to locate a piece of hardware that can accept arbitrary IP streams (be they MPEG-TS, H264, etc - the exact input ...
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39 views

Objective video quality assessment

I'm trying to develop a tool that given a video (without a reference video), it can measure the quality. Basically given some thresholds, it assigns them a rating (I just need 4 classes 1-4). Since we ...
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1answer
346 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
523 views

Setting different resolution for encoding and display when encoding in ffmpeg

I'd like to encode a video, say, in 960 x 720 but have video players automatically play it in 1280 x 720. I know how to do this in 2 steps, by first encoding in 960 x 720 (ffmpeg with -vf scale=960:...
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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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1answer
143 views

Add filter to prores file

I have captured some Mini-dv home videos to .avi. With ffmpeg I converted to prores v2 .mov files. Now i need to add yadiff filter.(interlaced -> noninterlaced) Is is possible to "update" my files ...
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openload.cc How can I extract encoding settings of videos?

My customer needs streaming service for his IP cameras and he ask me about same output quality as videos in openload.cc but I can´t simulate similar quality.I tried several encoding combination but ...
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1answer
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Downloading earlier segments from a live m3u8 playlist

I have an .m3u8 URI of type LIVE. As far as I know, live playlists use a sliding window instead of containing all the segments. My questions are, 1) Is it possible to find out what the length of the ...
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1answer
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Best encoding to fit 10hours of 1080p in 30gb?

I will be running a 10hour loop on a 1080p screen with only 30gb of storage. The loop will be created from a variety of 1080p .mp4s that will need to be compressed. (for example, one video is 12mins ...
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Using mediafilesegmenter on a video with edit lists

I'm trying to use mediafilesegmenter on a video I transcoded with ffmpeg to package it for HLS. However, it complains about "edit lists" and refuses to do anything. Does anyone know how to either ...
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1answer
903 views

Using AAC-HE for 5.1 audio?

A couple of questions when thinking about 5.1 audio encoding: What are the limitations of AAC-HE codec while doing 5.1 audio ? Why is AC3 preferred when compared to AAC-HE ?
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1answer
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To MP4V, or to DX50, or not to be

Should i compress my final outputs down to FOURCC of DX50 or MP4V? Tis the question. I'm having a hard time deciding on this, since im not really sure what to expect in future technology development....
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1answer
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How to avoid uploaded video being re-encode by Facebook

I just uploaded a video to Facebook yesterday, and then I tried to download the video as HD, and I realized that Facebook actually re-encode the video even though the original video file doesn't ...
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1answer
327 views

What do I need to learn in order to repair an ogv or ogg video that is defective? Where to start?

I recorded a video chat session with recordmydesktop in linux, but it is somehow defective. I give more details in a (big) footnote down here. I badly need to repair and play that video. Please put ...
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3answers
459 views

Good Intermediate Format for Combining Videos

I have a bunch of PNG files in separate directories that I'll turn into videos with FFMPEG. Say each clip will be a minute long. I then want to stitch those together into a final video. The final ...
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1answer
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What exactly is a “sample” in audio/video context?

I'm studying on video processing/encoding and doing so I started looking source code of some popular related tools. And all of them has some reference to "Sample" For example an arbitrary ...
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Resuming a partially-completed encode with FFmpeg

Summary Given a partially completed encode that: Was encoded using h264 in the Matroska container Was cut short by manually stopping FFmpeg by typing 'q' in the console ...what are the ways to ...
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vlc file format encoding issues

I am trying to figure out how to convert video and audio format with VLC. I'm trying to convert a 64 kbps mp3 to a 64 kbps ogg. The UI for encoding gives the options for audio as the following: ...
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1answer
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Stream video using FFmpeg with minimum writes reads to disk

We are streaming a video using a 30 instances of docker containers hosted on Azure each instance running FFmpeg. The problem is that Azure limits the reads/writes that a container can do. Is there a ...
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1answer
72 views

compare two video then cut the different

I have 2 video files with the same content, but coming from a different source. They have a slight difference in 'cut' and language dubbing, meaning one can be missing a shot compared to the other. I ...
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Script works on some files in batch but not others, any advice?

I'm trying to convert a batch of (mostly) .mxf files (4 channels of audio) to .mp4 files (stereo audio) taking the first two channels from the source using the following script: #!/bin/zsh for i in *....
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1answer
27 views

ffmpeg - Slow down video and loop/repeat audio

I am trying to use ffmpeg to slow down a video speed by 25% (75% speed) without changing the audio speed. ffmpeg -i input_video.mkv -filter:v "setpts=1.3*PTS" "SlowVideo25.mp4" On ...
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1answer
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Do modern devices support decoding 4:4:4 pixel formats?

I am recording and distributing relatively low motion screen content (not games). Using h264, fine text often appears very blurry due to the poor subsampling with 4:2:0 and 4:2:2 pixel formats. With 4:...
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Hevc Transparent Channel? (Apple WWDC19)

So, Up until now, HEVC Supported Transparent. But there wasn't any encoding Software To Encode that Transparent Pixels in it. Until Apple made their Own Way of Putting Alpha pixels inside a consumer ...
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Trim Audio Only of a Video file - FFMPEG

I have a mkv file containing a Video 1 minute shorter than audio. I want to Cut out first 1 Minute of Audio Stream. How Would I accomplish That With ffmpeg? I tried -ss 00:01:00.000, But that also ...
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Scale Video, Without 'ffmpeg Scaler' converting colorspace from RGBA to YUV

I have a video in RGBA space contained in MPNG codec. Which is in 4K. I need to Convert that into a 1080p File... SO i Used this - ffmpeg -i input.mkv -vcodec libx265 -vf scale=1920:1080 -sws_flags ...
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What SOFTWARE could I use to encode to this spec?

Thanks in advance! It's an mpeg transport stream in a .ts wrapper. Layout would be as follows: Video (MPEG2, 80Mbps, CBR, All I Frame,422@HL) Audio1 (Track1/PID1) 1 pair LPCM(SMPTE 302M)48kHz Audio2 ...
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108 views

ffmpeg 4.2.3 error, Could not find codec parameters for stream 4 (Unknown: none): unknown codec:

ffmpeg 4.2.3 error, Could not find codec parameters for stream 4 (Unknown: none): unknown codec: This error is for gopro videofiles, where they can processed very fine with different ffmpeg command......
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How to change orientation 180 degrees to only two videofiles out of multiple, with compression to happen only once?

How to merge with ffmpeg multiple action camera (gopro) video files (eg. 30+) into one, and change the orientation 180 degrees to only two of these video files with encoding / compression to happen ...

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