Questions tagged [webm]

Sponsored by Google, WebM is a new protocol used to convert audio/video files to HTML 5 compliant feeds.

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215 views

Colors change when converting GIF to VP9 WebM using FFmpeg

The colors come out fine when I try using VP8 WebM or H264 MP4, but whenever I use VP9 WebM there's a slight change in color. The change in color can be seen in Chrome, not sure about other browsers ...
0 votes
1 answer
249 views

Using FFmpeg to make a movie from PNG files: .WEBM with video filter blending error: Output file is empty

Commands: ffmpeg -framerate 0.5 -i %03d.png ffmpeg-framerate0.5.webm and ffmpeg -r 0.5 -i %03d.png ffmpeg-r0.5.webm create a working .webm videos, just as expected. But ffmpeg -framerate 0.5 -i %03d....
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0 votes
0 answers
295 views

FFMPEG throws error while converting WEBM/MP4 audio files from MediaRecorder to MP3

I use MediaRecorder to record the audio from the browser and then upload it to my server (ARM-based Linux machine - AWS Lambda Function, if it matters). Based on the browser type, I get either an MP4 ...
2 votes
1 answer
559 views

How to get duration of webm video file when duration is not explicitly defined

I have a segment of a webm file with an incomplete header, I want to cut this segment down to 10 seconds by trimming x seconds off the front of the file, however I am unable to use the -sseof tag ...
0 votes
0 answers
56 views

Convert this line to a VP8 line that allows me to render a PNG sequence

i want to convert this line ffmpeg -vcodec libvpx-vp9 -i original.webm -pix_fmt rgba frames/%04d.png that allows me to render a sequence png of a webm file that was originally in VP8
0 votes
0 answers
64 views

How to tag webm with ffmpeg (xubuntu / linux )?

How to tag webm with ffmpeg (xubuntu / linux ) ? OS: Ubuntu 20.04.4.LTS (flavour Xubuntu) I tried with VLC (GUI). I can edit the tags but vlc does not store my input. No error-message when "...
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0 votes
1 answer
533 views

With ffmpeg and input of a webm video file, how do I 'play the video'/output in real time to a new webm file and pipe to play in ffplay

Note, I am saying 'real time' in the description as I want the option in ffmpeg where it outputs the video in the same amount of time as the video takes to play. Sorry if I am using the wrong words to ...
1 vote
0 answers
3k views

How to convert MOV (with Alpha) to MP4 (with ALpha) - using FFmpeg [closed]

I am trying to convert a MOV (with alpha channel) to WebM and Mp4 (with Alpha channel) using FFmpeg. The WebM video is coming with the Alpha channel. But the video is not supported in SAFARI Browser. ...
1 vote
0 answers
1k views

FFMPEG - Transcoding webm to mp4 - wrong duration

I have a webm file that I want to convert to a mp4 file. The result is a mp4 file with a different duration than the webm (much longer). Webm file (via WeTransfer, example.webm, 421kb) About the ...
1 vote
1 answer
753 views

Convert WebM to Opus without encoding?

Tried all various commands with ffmpeg and also tried using mkvconvert and while they both instantly convert or extract the .opus from the .webm file.. the problem is the output file is always ...
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-1 votes
1 answer
547 views

Is there way to increase speed of adding subtitles to a WEBM video?

With MP4 I used this command ffmpeg -i INPUT.mp4 -vf ass=SUBS.ass -c:v libx264 -preset ultrafast -crf 22 -c:a copy OUTPUT.mp4 which has helped to increase the speed. But there are some problems with ...
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3 votes
1 answer
5k views

Fixing the length (duration) of a webm file takes too much time by ffmpeg

I have some webm files which lack duration/length. For example when I open one of them (which is about 20 minutes) by vlc media player I see something like this: This is very annoying because I ...
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1 vote
1 answer
318 views

ffmpeg fails when executing example command to convert using VP8

I am following the tutorial here, and executing the first example command yeilds an error. The ffmpeg version I have has libvpx and libvorbis enabled. When I run this command: ffmpeg -i aaa.mp4 -c:v ...
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0 votes
1 answer
430 views

Is it possible to recreate webms with a broken duration?

I've seen a few webms that have very unusual durations, even in the negatives. I've been trying to recreate it with ffmpeg, but I don't know enough of that program to make it work, if it would work at ...
1 vote
0 answers
259 views

Converting VP9 webm to VP8

I wonder how can I convert VP9 webm to VP8 with FFmpeg or Matroska (matroska would be better) without changing any kind of setting? I just want the output to be exactly same as the input but as VP8 ...
0 votes
1 answer
2k views

How to edit .webm files or convert them to good quality .gif, to edit in GIMP

I have a short scene from some TV show in a .webm format. I wanted to edit it, to create a simple funny animation/meme. I know how to edit .gif in a GIMP frame by frame, so I thought about converting ...
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0 votes
2 answers
2k views

Is it possible to make a webm file use a custom duration that is not the actual video's duration? And if so how?

Someone showed me a video where the duration counter would keep changing and another where there was a negative number as the duration, is there anyway to reproduce this? Both were webm files
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0 votes
1 answer
1k views

WebM With a Still Image and an Audio

How can I join together a cover and a music into WebM with the best audio quality using ffmpeg? I really can't figure it out.
2 votes
1 answer
874 views

Splitting corrupted webm video file

There's a 50-minute long webm video file which stops playing after about 8th minute. As I don't require the beginning of the video, I decided to split it and get last 30 minutes of it. For that, I ...
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3 votes
1 answer
3k views

Lossless VP9 Webm Encoding of PNG Sequence with Alpha in FFmpeg

I'm trying to encode a sequence of 32-bit 8bpc PNG images (RGB with an alpha channel) using the lossless VP9 codec with ffmpeg; specifically: ffmpeg -framerate 60 -i out%04d.png -c:v libvpx-vp9 -...
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12 votes
0 answers
6k views

Extracting Opus from WebM losslessly with FFmpeg or MKVToolNix

I have come across a strange problem when remuxing Opus audio stream from WebM to another container like ogg or opus. Running the output files through a spectrum analyzer clearly shows that there is ...
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-1 votes
1 answer
4k views

How do I remove all metadata from a WebM file?

I've tried using ffmpeg, but it seems to keep all the metadata I'm actively looking to remove. I'm looking to remove ALL metadata, including length, bitrate, etc. Before you say this isn't possible, ...
0 votes
1 answer
1k views

WEBM video looks correct in browsers, but not in video players

Ive been trying to figure out why a webm video renders incorrectly on my desktop... The correct file can be seen here, however, downloading the file, and trying to play it in VLC/MPC-HC produces a ...
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1 vote
2 answers
844 views

Find duplicate WEBM files

I have a large collection of files in webm format. Some of them are duplicates. They have totally different names, but their content is the same. It is annoying to find them by myself and then delete ...
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8 votes
1 answer
22k views

FFmpeg - convert WebM/Opus to WAV or FLAC in single step?

I want to create WAV and FLAC audio files from WebM files with Opus audio streams, and I want to do so without further degrading the audio. I am currently using a 2-step process as follows (WAV ...
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2 votes
1 answer
2k views

ffmpeg WebM to MP4: awful video quality

I'm trying to convert a WebM video coming from a webcam to an MP4 x264 format. I tried to use this ffmpeg command: ffmpeg -stats -nostdin -y -flags global_header -i "/home/Foto/incoming-video/2017-05-...
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3 votes
0 answers
691 views

What is the difference between webm and webm_chunk?

I am asking because I cannot check this myself, when running ffmpeg with "webm_chunk" format I get either "Output file #0 does not contain any stream" or "Could not write header for output file #0" ...
2 votes
1 answer
2k views

FFmpeg fails to convert webm files when h264_nvenc forced

I have been working with below environment. ==>Ubuntu 16.04.3 ==>FFmpeg :3.4.2 -- configuration: --prefix=/usr/local/ffmpeg_new/ --enable-cuda --enable-cuvid --enable-nvenc --enable-nonfree --...
68 votes
2 answers
16k views

What does Matroska have which WebM doesn't, that made the differentiation necessary?

I've read that WebM is essentially a subset of the Matroska format. What does Matroska support that WebM doesn't, which necessitated "christening" a new format rather than just saying "...
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8 votes
1 answer
10k views

Is it ok to rename webm (audio-only) files to .opus?

For .webm files obtained with youtube-dl -f bestaudio containing no video stream, is it preferable to run ffmpeg -i input.webm -vn -c:a copy output.opus or can one simply rename the source file, ...
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2 votes
0 answers
182 views

How can I inspect the file structure of DASH injected webM files?

So we know after injecting DASH information, WebM files will have the init chunk and index chunk for DASH. How can I inspect the structure of the WebM files to understand the position of these chunks ...
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3 votes
0 answers
675 views

Converting video int Webm using ffmpeg, file size

I have found this article from google describing how to convert video into webm https://sites.google.com/a/webmproject.org/wiki/ffmpeg/vp9-encoding-guide I used following command to convert video ...
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1 vote
1 answer
2k views

ffmpeg - Is it possibe to retain real timecodes using -copyts?

It's is a simple task. I want to make a converted clip of a video using -copyts to have it's real timecodes. For example, the converted clip of this command: ffmpeg -hide_banner -ss 57:41.76 -i input....
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1 vote
2 answers
4k views

Extract alpha channel from webm video

I'm trying to extract a mask from a webm video with alpha transparency: ffmpeg -i test.webm -vf "alphaextract" -y output.mp4 But I'm getting an error: [Parsed_alphaextract_2 @ 0x7f924b700d00] ...
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0 votes
0 answers
507 views

FFmpeg script to convert all WebM files in a folder to Gif, and then delete the WebM files

I'm using FFmpeg with DirectoryMonitor, a folder watching program. When a webm is added to the folder i want to execute a script to convert all webm files in that folder to gif, and then delete those ...
1 vote
1 answer
805 views

FFMpeg image sequence to video using VP9 encoder

I'm trying to transcode mp4 to webm format in a lossless way. I tried two ways to do that. For that purpose, I extracted mp4 video to image sequences (png). Then, I converted image sequence(without ...
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1 vote
1 answer
466 views

How do I transcode/compress mp4 source files on the Linux command line?

I have some rather large mp4s produced by my phone. They aren't very long, so they're probably not very compressed. What's an example of using a command line Linux tool to transcode one of these to ...
4 votes
1 answer
8k views

Correcting for wildly incorrect time of .webm with FFMPEG

I have a file that when I run ffpmeg -i on it will display a time of 351909:41:29.64. I know I didn't record for 40 + years. Any suggestions on what would be the best way to fix this? I ...
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0 votes
1 answer
61 views

How can I locate a local html file that has been loaded into the browsers element inspector?

Since there don't seem to be any video players with a seamless loop, I've been opening my webms through Firefox since the webm player is capable of seamless looping. Problem is every time I open a ...
1 vote
1 answer
4k views

How can I convert a series of images to WebM in FFmpeg?

I’ve got a series of JPG images going from 108-AN-001 to 108-AN-045. I need to convert these into a single WebM video file. I've tried this command: ffmpeg -f image2 -i 108-AN-%03d.jpg -vf 12 output....
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0 votes
1 answer
2k views

How to mux Vorbis audio and VP8 video into WebM format with ffmpeg?

I have a Vorbis audio and VP8 encoded video, and would like to mux them into WebM format. How do I mux them with FFmpeg, and also set the display aspect ratio to 16:9? I'm using Windows 7 with the ...
0 votes
1 answer
2k views

How to Resize WEBM Videos

I find that a lot of the webm videos (or gifv) on imgur and the like are too small to see (yes, my eyesight is horrible). These types of videos allow for viewing in full screen, but since the source ...
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0 votes
2 answers
936 views

Compiling libvorbis with MinGW

I'm attempting to cross compile libvorbis ready to then do the same for libvpx to ultimately compile a windows version of ffmpeg that can handle WebM (along with a few other options that I've yet to ...
-1 votes
1 answer
883 views

FFMPEG conversion from webm to mp4 intermittent on Ubuntu 14.04 [duplicate]

I am trying to convert .webm file that we get from google's screencastify to .mp4 file. I need it to be playable using Windows Media Player. I need it the file to be playing with all the WMP versions ...
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5 votes
3 answers
14k views

Conversion from WebM to MP4 in Ubuntu is slow and bad quality

I have used the command ffmpeg -i input.webm -q:v 10 -c:a copy out.mp4 I also tried using avconv instead of ffmpeg. The conversion is successful but the quality is bad. Also it takes a lot of time. ...
  • 137
27 votes
3 answers
113k views

What's the easiest way to save a GIFV as a simple GIF?

Usually I open the context menu right clicking on the image. Now theres no option for "save image as", just options for the WEBM/MP4 format.
0 votes
4 answers
3k views

combining 1 image + 1 audio using FFmpeg

I want to combine an audio file and one image file into a video. Output will be in .webm format so I will be using libvpx. The video must have one frame with the best/lossless quality. So far I have ...
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0 votes
1 answer
2k views

ffmpeg constant rate factor for different webm qualities

So i came across the following question What is the right way to calculate 1080p 720p 360p 240p quality? But that is for H264 MP4 files. For MP4 files i set the -crf constant rate factor as 18 for ...
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8 votes
1 answer
842 views

IE will not seek audio/webm file

I'm trying to create a WebM audio file that will play back and seek in all browsers using the HTML5 <audio> tag and MIME type audio/webm. I've found workarounds to get this to work in all ...
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0 votes
0 answers
125 views

Video is not playing on any of browsers

When I am trying to open Google Material Design Spec and click on play button nothing happens. Checked on Chrome, Opera, Firefox. When I am trying to open video url directly, first time - it doesn't ...