Questions tagged [transcoding]

The process of converting a media file from one format to another or changing the compression settings used.

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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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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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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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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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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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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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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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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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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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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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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 ...
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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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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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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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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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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 ...
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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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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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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 ...
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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 ...
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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/...
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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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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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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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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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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 ...
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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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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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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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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 ...
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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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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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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 ...
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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, ...
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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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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% ...
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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 ...
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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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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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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 ...
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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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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 ...
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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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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 ...
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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) ...
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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/...
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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 ...
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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 ...