Questions tagged [transcoding]
The process of converting a media file from one format to another or changing the compression settings used.
131
questions
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22 views
Converting a DPX image sequence with ffmpeg
I am trying to convert an 10 bit RGB DPX image sequence, captured with the Blackmagic Intensity Pro from a PAL source, to a video with ffmpeg.
My problem with that is, that I can create from the DPX ...
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27 views
How to view expansion of options ffmpeg uses when specifying -target?
I am trying to convert a video to NTSC so I can make a DVD out of it, and to do so I am using the following command:
ffmpeg -i input.mp4 -target ntsc-dvd output.mpg
I know that the -target ntsc-dvd ...
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0answers
40 views
Gop structure changed after transcoding
I need transcode file to XDCAM HD422. I use something like the following command (it's only part of command, but that's enough to reproduce my problem).
ffmpeg -i pathToFile -ss 00:00:00 -t 00:00:30 -...
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31 views
I want to convert .mp4 to .ts using H264 at constant framerate 25fps
I've been trying to do this conversion for a couple of days reading through forums
ffmpeg -i in1.mp4 -vcodec libx264 -s 720x576 -vf "fps=25"-vsync cfr -b:v 2300k -acodec aac -b:a 128k out1....
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1answer
43 views
Does transcoding or compression occur when importing and editing .mts (.mp4) video files?
If a .mts video file is opened or imported to a project in a video editor like Adobe Premiere Pro, is transcoding going on? Video or audio compression? If so, why, instead of editing the raw file as ...
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1answer
33 views
Does recording desktop audio reduce quality?
If I record audio (say, a 320 kbps mp3) that's playing through my desktop audio (in, for example, Audacity with loopback, or OBS) is the quality going to be reduced if I compare the recording to the ...
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2answers
77 views
Halve framerate without complete re-encoding
Is there any tool that can manipulate / transcode h264 or h265 video streams throwing away approximately half of the frames, without performing a full re-encode?
I'm thinking it would be theoretically ...
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1answer
332 views
How to preserve colorspace in ffmpeg
I have a x264 video with yuvj420p(pc, smpte170m) color space and i want to convert this video to x265 and reduce its file size. I have used this command ffmpeg -i input.mp4 -vcodec libx265 -crf 20 ...
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1answer
19 views
can I use ffmpeg drawtext filter as a passthrough/identity filter? (and/or performance question)
Background: I have a script which needs to apply a variable number (from zero to 'a few') drawtext filters to a base stream, and I'm trying to balance performance and coding/maintenance concerns. ...
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1answer
217 views
ffmpeg conversion - vp8 with alpha
I'm trying to convert a mov file (with alpha channel) to webm, vp8 with alpha, on windows.
ffmpeg -i C0016.mov -s 960x540 -vcodec vp8 -pix_fmt yuva420p -metadata:s:v:0 alpha_mode="1" ...
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1answer
125 views
How can one resume an interrupted ffmpeg job or pause by design and save some kind of state file?
Attempting to convert a series of mp4's for the umpteenth fricking time using hvec 265 codec to save a buttload of storage space. And this does indeed work quite well but i do not have the luxury of ...
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24 views
Video coding : H264 is transcoded to H265. Result looks sharper despite lower bit rate. What is most likely explanation?
Video coding : H264 is transcoded to H265 using "slow" preset.
When playing the video files (using VLC), the result looks sharper despite lower bit rate (10 Mb/s --> ca 1.5 Mb/s) and ...
0
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0answers
18 views
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
150 views
Create 4x2 grid mosaic
trying to create a 4x2 grid from 8 videos using the terminal on a mac. The code I am using is not working:
ffmpeg -i input0.mov -i input1.mov -i input2.mov -i input3.mov -i input4.mov -i input5.mov -i ...
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0answers
269 views
FFMPEG: Convert WebM VP8/VP9 multi-resolution video to MP4 (H.264)
I have been trying to convert a multi-resolution WebM video ( VP9/VP8/H.264 ) (1280 x 1080 till the half, thereafter 1080 x 1280) to MP4 container with H.264 encoding for video.
When transcoded with ...
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0answers
23 views
Transcoding BlueRay's gives inconsistent filesizes
When I rip a BlueRay, the output file is usually between 15-30 GB. That's too large for archiving on my NAS, so I'd like to compress them down further.
I'm targeting 6-8GB for 1080p movies. Obviously ...
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0answers
13 views
Post-production editing audio/video out of sync
I am trying to add two videos using ffmpeg and the output video/audio is out of sync (and fast forwarded).
Goal is to put intro.mp4 before the original file clip.flv
My approach is to
Change the ...
1
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2answers
289 views
Best strategy to keep aspect ratio consistent for all videos having any resolution
I am using the following ffmpeg command to create multiple resolutions for the same video content.
ffmpeg -i ${f} -c:v libx264 -keyint_min 150 \
-g 150 -profile:v main -f h264 -dash 1 \
-an -vf scale=...
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0answers
37 views
Best ffmpeg configuration for universal video codec compatabiltiy across browsers
I intend to get a transcoding setting to support all browsers at the same time including, chrome, firefox and safari.
Currently I am using following, yet this does not provide a valid video with ...
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2answers
682 views
FFMPEG: is it possible to offset output frames from a selection of specific frames?
I'm doing some ffmpeg (4.1.3) transcodings by extracting specific frames from the source, in this case, the source can be either a movie or an image sequence, all working fine with the following ...
0
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1answer
86 views
Create one split screen video, separate audio streams and a thumbnail from the resultant split screen video - all in one pass
I'm using ffmpeg to create several single splitscreen videos out of 2 separate videos. The 2 videos have audio so I want to extract the 2 video's audio streams as 2 separate mp3s and also create a ...
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256 views
FFMPEG -C:V Copy and -C:V Transcode
When I do it like this,
-c:v copy -preset ultrafast -cfr 20 -tune zerolatency
and it doesn't work I know that this is excpected because the video codec is copied and all the other parameters such as ...
0
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1answer
40 views
Recommandation for on-premises video file transcoding server accessible via REST API?
I am looking for a video file transcoding solution that I can run on an on-premises server and access via a REST API.
While I found lots of commercial cloud services (e.g. https://www.filestack.com/...
2
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1answer
2k views
Intra-frame H.264 / H.265 compared to DNxHR or Prores as intermediate codecs for editing
IMPORTANT: ISSUE SOLVED (STILL A COUPLE OF QUESTIONS, THOUGH), I POSTED SOME INFO BELOW THE ORIGINAL POST AS AN UPDATE IF SOMEONE FINDS THIS USEFUL:
Quick question: what are the advantages of using ...
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0answers
652 views
FFmpeg: DNxHR 444 10 bits transcoding issue (HDR project). SMPTE2084 unsupported?
I have a couple of questions regarding intra-frame codecs for editing purposes (in Premiere Pro).
UPDATE (01/24/20). More details of the original issue after this:
I seem to have encountered a dead ...
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2answers
1k views
FFmpeg does not preserve colors after resizing
I would like to resize a 4K mkv video to 1920×1080 with ffmpeg version 3.4.6-0ubuntu0.18.04.1 on Ubuntu 18.04. The original file has the following features:
Input #0, matroska,webm
encoder : ...
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0answers
167 views
Adobe Encoder Desyncs Video/Audio (MTS to MP4)
I've been trying to transcode an MTS (recorded on a Panasonic) to MP4 with Adobe Media Encoder. The audio/video has consistently gone out of sync. I've matched the source, gone over all the settings, ...
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0answers
268 views
ffmpeg ProRes to MP4 Alters Colors Slightly
I cannot for the life of me figure out what is going wrong, but I have a ProRes MOV file with the following specifications:
And I want to convert it to a 4:2:0 MP4 video file. Every time I attempt ...
0
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1answer
139 views
Can you encode intra-frame videos from inter-frame without loss?
I'm aware of the differences between intra and inter, but I'm not the most savvy about reencoding them after the fact. Is encoding with intra from an inter-coded video the same as if you originally ...
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1answer
1k views
ffmpeg: Preserve timecode when converting mov to mp4
This seems simple enough. I want to do a basic conversion of a .mov file to a .mp4 file using ffmpeg. The hitch seems to be that I also need to preserve the timecode.
I've looked at many posts from ...
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1answer
1k views
Why does Nvenc Encoder improve decoding speed?
I am trying to improve the speed of decoding H.264 frame to RGBA frame using FFmpeg in C++. I have found a CLI command that can do that but I still do not fully understand the command to reproduce it ...
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0answers
274 views
Best way to handle stream with ffmpeg and GPU
So in my project, I need to capture a video stream, decode the video, run the individual frames through an object detection algorithm and then play the output as a video.
This whole operation is ...
0
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1answer
160 views
Video Assets to test transcode quality
I was wondering if anyone knows from where I could get a few (short) video assets in high bitrate to check the quality output of a transcoder.
Some context: A few years ago I was working on a VOD ...
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2answers
42 views
How to transcode HEVC footage on a mac if you don't have CC2018 yet [duplicate]
Is there a good free way to convert iPhone HEVC footage to .mov prores or something similar using a Mac (MacOS 10.12) with Premiere CC 2017? Googling provides lots of unreliable looking apps from ...
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0answers
123 views
Improve FrameServer performances
I followed ffmpeg guide to install debugmode frameserver.
All works fine except with the fact that the frames served does not goes up to 25 fps. FFmpeg reports a speed of 0.9x..
My initial goal ...
0
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1answer
678 views
FFMpeg set language as Unknown or unspecified in a QuickTime MOV
I have to transcode with FFMpeg some video with multiple audio where various audio track are not language related, just music and so on.
I would like to assing as language something like Unspecified, ...
0
votes
1answer
255 views
If I use a normal build of ffmpeg how take advantage of video acceleration for scale?
I generally use ffmpeg for encode in h264 and also resize media
My common command is something like:
ffmpeg -i in.mov -c:v libx264 -preset ultrafast -b:v 5000k -s:v 1280x720 out.mov
I have an ...
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2answers
1k views
How to concatenate 2 MP4 videos to output of certain bitrate?
I've already read the other articles about concatenating but couldn't find any that discuss specifying the output bitrate.
I have 2 MP4 videos.
What I want to do is speed up the first video to 110% ...
2
votes
1answer
3k views
How to choose the right bitrate, H.264 profile and level for Web Video presentation?
I want to start producing videos and looking around the internet for usual bitrate ranges (VBR) and H.264 profiles and levels for Web Video exports.
I found some guides with Vimeo and YouTube and ...
5
votes
3answers
859 views
How should I interpret the results from Netflix VMAF
I've been encoding some clips and then analyzing them with the VMAF tool from Netflix, but I don't know how to understand the results.
This is the overall mean section of one of my tests.
...
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1answer
600 views
Transcode each stream in a different thread with ffmpeg
Is there a way of forcing ffmpeg to encode each audio stream in a different thread?
ffmpeg
-i audio1.ac3 -c:a libopus
-i audio2.ac3 -c:a libopus
-i audio3.ac3 -c:a libopus
output.mkv
...
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0answers
36 views
broacast tv specs.
can any one help me about how can i deliver this specs for a broadcast tv channel ? :
im using fcpx and compressor 4. do i need any other app or can i manage it with those ?
which specs i do on fcp ...
0
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1answer
200 views
Blu-ray transcode to H.265 using Intel Quick Sync Video
Blu-ray transcode to H.265 using Intel Quick Sync Video
I just started a process of transcoding about 100 video discs (with DTS-HD Master Audio on passthrough) from my collection of Blu-rays and want ...
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0answers
2k views
Encode or Transcode with ffmpeg and libx264 as fast as possible
I'm trying to tune out ffmpeg to squeeze as much fps as possible from my server machines with lot of cores.
Sometimes expecially when there's also a scale (eg: shrinking down from 4k to full hd or ...
3
votes
1answer
2k views
ffmpeg transpose=clock rotates 180 degrees instead 90
I have 2 similar videos created on the same mobile. The first one can be downloaded here.
If I'm using the following command the result is correctly rotated by 90 degrees:
ffmpeg -i 20180114_193135....
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1answer
2k views
Transcode 5.1 audio in ffmpeg leads to incorrect audio mapping in output
I need to transcode some high res videos (prores or dnxhd files with 5.1 uncompressed 48kHz audio in MOV container) to their low res h264 with AAC keeping the audio still in 5.1 preserving their ...
4
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1answer
5k views
RTSP to RTMP converting fails after specific time only when IP camera enters night mode
I have bought a cheap IP camera Escam QF002 producing output in RTSP.
I'd like to secure it with RTMP or HLS stream served by nginx with nginx-rtmp-module.
For this I'd copy the video stream (h264) ...
1
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1answer
1k views
How to make ffmpeg flush the subtitles in real time while transcoding?
I'm feeding ffmpeg from stdin and do several transcoding operations in one command only. The issue is that ffmpeg seems to transcode them(or at least write on disk) sequently (i.e. first it transcodes/...
1
vote
1answer
2k views
Convert video from 24 fps to 25, shortening length (no frame duplication), keeping audio pitch
I have a .mov video with 24fps and 5.1 audio.
Is it possible change the framerate from 24 to 25 fps with no frame resampling (no frame duplication / removal - just new framerate interpretation) and ...
1
vote
2answers
209 views
Encoding low bitrate video source file to a higher bitrate
I need to know if there will be any difference in the quality of the encoded video if the bitrate of the source file is, let's say 2000kbps and I encode it to 4000kbps.
Any help will be much ...
