Hello I get this error when i want to capture my screen on linux with ffmpeg ubuntu 16:04 : the command i'am using : $ ffmpeg -f x11grab -r 15 -s 1920x1080 -i :0.0+0,0 -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video0 ffmpeg version 4.1.1-0york1~16.04 Copyright (c) 2000-2019 the FFmpeg developers built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.11) 20160609 configuration: --prefix=/usr --extra-version='0york1~16.04' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-nonfree --enable-libfdk-aac --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared libavutil 56. 22.100 / 56. 22.100 libavcodec 58. 35.100 / 58. 35.100 libavformat 58. 20.100 / 58. 20.100 libavdevice 58. 5.100 / 58. 5.100 libavfilter 7. 40.101 / 7. 40.101 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 3.100 / 5. 3.100 libswresample 3. 3.100 / 3. 3.100 libpostproc 55. 3.100 / 55. 3.100 [x11grab @ 0x5611f156e540] Cannot open display :0.0+0,0, error 1. :0.0+0,0: Input/output error

I have a Kodi video library where each movie is in its own folder because I had to place .nfo files with links to TMDB in each folder to ensure correct identification. The movies are in their original Blu-ray resolution, stored on a drive shared over Samba on a gigabit LAN. I need to transcode all these files with FFmpeg to max. 1334×750 px. Setup: Intel Core i-7 3930K, 2 x NVIDIA GTX 980 6 GB GPU, KDE on Debian Testing, custom FFmpeg compiled with h264_nvenc enabled. Although the GPUs are connected with an SLI bridge, they're not in SLI mode due to NVIDIA's Linux driver limitation (v550.163.01). GPU 0 is used by the system, GPU 1 is idle. How to do it efficiently?

I am wondering why, when using vaapi with ffmpeg, if I use x11grab I must use -vf format=nv12,hwupload but with kmsgrab I must use -vf scale_vaapi=format=nv12 instead. In particular I want to know 2 things. - Why is it this way? - Is there any way to use normal filters (like eq=brightness=50 or zscale) with vaapi when using kmsgrab? Because the dilemma that's causing me to ask these questions is that I need to do some color corrections and filters seem like the best way to do that, but I'm unable to use filters when I'm using kmsgrab because scale_vaapi breaks other filters, and I even tried using some obscure filters like procamp_vaapi which shuold allow me to do the same things as eq, but I couldn't get it to work. my kmsgrab command: ffmpeg -y -device /dev/dri/card1 -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi,scale_vaapi=format=nv12' -c:v h264_vaapi -qp 24 output.mkv

Someone suggested I direct a copy of the unmodified X display to a file and afterwards convert that file to a general purpose video file. What commands would I use to do this on a Kubuntu system? (Edit: He said something about attaching a display port to a file.) If not possible, what is my best option for an excellent quality screen recording that does not depend on fast hardware? *Background:* I tried using avconv with -f x11grab and some GUI programs. However, no matter what I try, the resulting video either has artifacts/ blurriness or is choppy (missing frames). This is probably due to CPU/ memory constraints. *Goals:* - Video quality must not be noticeably different from seeing the session directly on a screen, because the purpose is to demonstrate an animated application. - The final video must be in a common format that can be sent to Windows users and used on the web. I think H.264 MP4 should work. - The solution should not presume much prior knowledge. I am familiar with the command line and basic Linux commands, but I am still learning Linux and do not know much about video codecs. *What I already tried:* - Best command so far: ffmpeg -f x11grab -s xga -r 30 -i :0.0 -qscale 0.1 -vcodec huffyuv grab.avi, then convert to mp4 with ffmpeg -i grab.avi -sameq -vcodec mpeg4 grab.mp4. - The picture quality is great, but on my test sytem it lags the computer. On a faster target system it does not lag, but frames are obviously skipped, making the video not very *smooth*. - I am still trying to figure out how to save the grab.avi file to SHM to see if that helps. - Using Istanbul and RecordMyDesktop GUI recorders - Simple command: avconv -f x11grab -s xga -r 25 -i :0.0 simple.mpg using avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1 - Adding -codec:copy (fails with: Requested output format 'x11grab' is not a suitable output format) - Adding -same_quant (results in great quality, but is very choppy/ missing many frames) - Adding -vpre lossless_ultrafast (fails with: Unrecognized option 'vpre', Failed to set value 'lossless_ultrafast' for option 'vpre') - Adding various values of -qscale - Adding various values of -b - Adding -vcodec h264 (outputs repeatedly: Error while decoding stream #0:0, [h264 @ 0x8300980] no frame!) - Note: h264 is listed in avconv -formats output as DE h264 raw H.264 video format

I've figured out a way to capture video on wayland (hyprland) with ffmpeg, but that method does not cover audio. Most people on wayland will be using pipewire, pipewire has a compatibility layer for pulseaudio called pipewire-pulse which allows most audio designed for pulseaudio to be played or recorded through pipewire. But in ffmpeg's case it doesn't seem to work. ffmpeg -device /dev/dri/card1 -vaapi_device /dev/dri/renderD129 -f pulse -ac 2 -i easyeffects_sink.monitor -c:a libopus -framerate 60 -f kmsgrab -i - -c:v h264_vaapi -rc_mode QVBR -q:v 10 -maxrate 327680 -b 81920 -pix_fmt vaapi -vf hwmap=derive_device=vaapi,scale_vaapi=format=nv12:out_range=full out.mp4 The above command fails with Option device not found. Error opening input file easyeffects_sink.monitor. Error opening input files: Option not found But if I remove this part: -f pulse -ac 2 -i easyeffects_sink.monitor -c:a libopus It will work relatively fine. and if I am on x11 instead of wayland, using x11grab instead of kmsgrab ffmpeg -vaapi_device /dev/dri/renderD129 -f pulse -ac 2 -i easyeffects_sink.monitor -c:a libopus -video_size 2560x1600 -framerate 60 -f x11grab -i :1.0 -c:v h264_vaapi -rc_mode QVBR -q:v 10 -maxrate 327680 -b 81920 -pix_fmt vaapi -vf format=nv12,hwupload out.mp4 That command works perfectly fine even if it uses the exact same options that didn't work on kmsgrab. Which leaves me with the question of whether ffmpeg is capable of capturing audio from a wayland environment at all.

Goal is to capture video from my old usb webcam (device 0733:0430). Trying to save video gives this error. (I've tried both ffmpeg and avconv.) Command ffmpeg -f v4l2 -i /dev/video2 -s 160x120 tmp.mkv [video4linux2,v4l2 @ 0x815280] Time per frame unknown [video4linux2,v4l2 @ 0x815280] Cannot find a proper format for codec 'none' (id 0), pixel format 'none' (id -1) Assertion *codec_id != AV_CODEC_ID_NONE failed at /build/buildd/ffmpeg-2.3/libavdevice/v4l2.c:802 I know it can work on Linux, because I had it running a few years ago. How to get it to work now? ---- **Below is information about the device.** Device dmesg output [53008.270283] usb 2-1.2: new full-speed USB device number 4 using ehci-pci [53008.363405] usb 2-1.2: New USB device found, idVendor=0733, idProduct=0430 [53008.363416] usb 2-1.2: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [53008.779745] gspca_main: v2.14.0 registered [53008.809496] gspca_main: spca505-2.14.0 probing 0733:0430 [53008.812508] usbcore: registered new interface driver spca505 ffmpeg -list_formats 1 -f v4l2 -i /dev/video2 [video4linux2,v4l2 @ 0xbed5e0] Raw : Unsupported : S505 : 160x120 176x144 320x240 352x288 v4l-info /dev/video2 ### v4l2 device info [/dev/video2] ### general info VIDIOC_QUERYCAP driver : "spca505" card : "USB Camera (0733:0430)" bus_info : "usb-0000:00:1d.0-1.2" version : 3.13.11 capabilities : 0x85000001 [VIDEO_CAPTURE,READWRITE,STREAMING,(null)] standards inputs VIDIOC_ENUMINPUT(0) index : 0 name : "spca505" type : CAMERA audioset : 0 tuner : 0 std : 0x0 [] status : 0x0 [] video capture VIDIOC_ENUM_FMT(0,VIDEO_CAPTURE) index : 0 type : VIDEO_CAPTURE flags : 0 description : "S505" pixelformat : 0x35303553 [S505] VIDIOC_G_FMT(VIDEO_CAPTURE) type : VIDEO_CAPTURE fmt.pix.width : 160 fmt.pix.height : 120 fmt.pix.pixelformat : 0x35303553 [S505] fmt.pix.field : NONE fmt.pix.bytesperline : 160 fmt.pix.sizeimage : 28800 fmt.pix.colorspace : SRGB fmt.pix.priv : 0 controls VIDIOC_QUERYCTRL(BASE+0) id : 9963776 type : INTEGER name : "Brightness" minimum : 0 maximum : 255 step : 1 default_value : 127 flags : 32

all. Hope you guys are doing well. I have downloaded a 28min mp4 from a site but its audio and video got downloaded into 2 separate mp4 file both of 28min. Now how can I merge them? Thanks in advance Attaching ffprobe info for those file below

Is it possible to record the screen with ffmpeg on wayland using the Hyprland compositor? I've read some posts that imply people managed to do it with kmsgrab, but cannot figure out how to do it myself (I tried the common examples with kmsgrab and it didn't work, possibly because I'm on wayland) Is there a way to do it? I've tried: ffmpeg -device /dev/dri/card1 -f kmsgrab -i - -vf 'format=nv12,hwupload' -c:v h264_vaapi output.mkv But get the following error: [kmsgrab @ 0x556c9ae1fec0] Using plane 58 to locate framebuffers. [kmsgrab @ 0x556c9ae1fec0] Template framebuffer is 142: 2560x1600 format 34325258 modifier 200000000401b03 flags 2. [kmsgrab @ 0x556c9ae1fec0] No handle set on framebuffer: maybe you need some additional capabilities? [in#0 @ 0x556c9ae1fc00] Error opening input: Invalid argument Error opening input file -. Error opening input files: Invalid argument Recording with vaapi with wf-recorder or wl-screenrec works fine btw, but I would prefer to directly use ffmpeg. I'm also curious if it can be used with nvenc (which would be on card0 for me), but if I try to use it with my nvidia gpu I get: [kmsgrab @ 0x558916595e80] No usable planes found. [in#0 @ 0x558916595bc0] Error opening input: Invalid argument Error opening input file -. Error opening input files: Invalid argument

How can I use [ffmpeg](https://ffmpeg.org/) to reduce the size of a video by lowering the quality (as minimally as possible, naturally, because I need it to run on a mobile device that doesn't have much available space)? I forgot to mention that when the video can use subtitles (*.srt or *.sub), I'd like to convert them too to fit the parameters of the converted video file.

I'd like to only see those lines containing "Stream #" from an ffprobe output. But whatever I do, it continues to show the whole output. Neither "|" nor ">" pipes work. What’s the magic? Thanks a lot! ffprobe -v info video.mp4 | grep "Stream #"

I am unable to send a stream to my ffserver. I started the server with ffserver -f /etc/ffserver.conf & where ffserver.conf has not been modified. I tried sending a webcam stream with ffmpeg -f alsa -ac 2 -i plughw:0,0 -f video4linux2 -s vga -i /dev/video0 http://localhost:8090/feed1.ffm I have however the following error: [...] [tcp @ 0x560e1234c6e0] Connection to tcp://localhost:8090 failed (Connection refused), trying next address [...] MPEG-1/2 does not support 3/1 fps [...] The port 9080 is open, as seen with nmap localhost **Why do I have this error and how to send my stream?** ----------------------------- **Full output:** # ffmpeg -f alsa -ac 2 -i plughw:0,0 -f video4linux2 -s vga -i /dev/video0 http://localhost:8090/feed1.ffm ffmpeg version 3.2.1-1 Copyright (c) 2000-2016 the FFmpeg developers built with gcc 6.2.1 (Debian 6.2.1-5) 20161124 configuration: --prefix=/usr --extra-version=1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-libtesseract --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-libopencv --enable-frei0r --enable-libx264 --enable-chromaprint --enable-shared libavutil 55. 34.100 / 55. 34.100 libavcodec 57. 64.101 / 57. 64.101 libavformat 57. 56.100 / 57. 56.100 libavdevice 57. 1.100 / 57. 1.100 libavfilter 6. 65.100 / 6. 65.100 libavresample 3. 1. 0 / 3. 1. 0 libswscale 4. 2.100 / 4. 2.100 libswresample 2. 3.100 / 2. 3.100 libpostproc 54. 1.100 / 54. 1.100 Guessed Channel Layout for Input Stream #0.0 : stereo Input #0, alsa, from 'plughw:0,0': Duration: N/A, start: 1481703954.356244, bitrate: 1536 kb/s Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s Input #1, video4linux2,v4l2, from '/dev/video0': Duration: N/A, start: 41830.241126, bitrate: 147456 kb/s Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc [tcp @ 0x560e6432c6e0] Connection to tcp://localhost:8090 failed (Connection refused), trying next address [tcp @ 0x560e64345a40] Connection to tcp://localhost:8090 failed (Connection refused), trying next address [mpeg1video @ 0x560e6435fb20] bitrate tolerance 21333 too small for bitrate 64000, overriding [mpeg1video @ 0x560e6435fb20] MPEG-1/2 does not support 3/1 fps Stream mapping: Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp2 (native)) Stream #1:0 -> #0:1 (rawvideo (native) -> mpeg1video (native)) Stream #0:0 -> #0:2 (pcm_s16le (native) -> wmav2 (native)) Stream #1:0 -> #0:3 (rawvideo (native) -> msmpeg4v3 (msmpeg4)) Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height **Full /etc/ffserver.conf** (no modification from original file): HTTPPort 8090 HTTPBindAddress 0.0.0.0 MaxHTTPConnections 2000 MaxClients 1000 MaxBandwidth 1000 CustomLog - File /tmp/feed1.ffm FileMaxSize 200K ACL allow 127.0.0.1 Feed feed1.ffm Format mpeg AudioBitRate 32 AudioChannels 1 AudioSampleRate 44100 VideoBitRate 64 VideoBufferSize 40 VideoFrameRate 3 VideoSize 160x128 VideoGopSize 12 Feed feed1.ffm Format asf VideoFrameRate 15 VideoSize 352x240 VideoBitRate 256 VideoBufferSize 40 VideoGopSize 30 AudioBitRate 64 StartSendOnKey Format status ACL allow localhost ACL allow 192.168.0.0 192.168.255.255 URL http://www.ffmpeg.org/

I am unable to play videos on my Ubuntu 18.04.3 system running in VirtualBox due to the error message Mpeg-4 AAC decoder not installed. The file requires MPEG-4 AAC decoder and H.264 (Main Profile) decoder, which are not installed. How can I fix this issue?

I want what is essentially a kiosk, to display a video stream using ffplay, without a whole Desktop environment. I started with minimal CentOS7, and installed xterm and X11, per this simple guide: https://linuxconfig.org/how-to-run-x-applications-without-a-desktop-or-a-wm I've created a .xinitrc file:

#!/bin/bash
exec firefox

and when I execute startx, it opens an X11 window containing Firefox. But, when I replace the .xinitrc file with this one:

#!/bin/bash
exec ffplay udp://192.168.0.237:5444

I just get a blank screen, in spite of knowing that ffplay command is right. Though I can tell from ps -ef | grep ffplay that ffplay is indeed executing. I think it is just piping the output video someplace different from where Firefox did. I don't know how to tell where that is, nor how to force it to go to localhost:0.0. Note the CentOS7 box is a Hyper-V VM, which I am accessing via a Hyper-V console.

I tried to convert a high-resolution video to 2k. I used this command:

ffmpeg -i input_video.mp4 -vf scale=1920:1080 -c:v h264_nvenc -preset slow -b:v 8M output_video.mp4

Based on the top and nvidia-semi results, my CPU was at maximum utilization, but my GPU was barely used. The ffmpeg process only used about 240 MiB of vram. nvidia-smi dmon did show lots of enc activity. But the low vram usage and high CPU utilization makes me wonder if ffmpeg is fully utilize my GPU.

nvidia-smi dmon                                                                                     
# gpu    pwr  gtemp  mtemp     sm    mem    enc    dec    jpg    ofa   mclk   pclk
# Idx      W      C      C      %      %      %      %      %      %    MHz    MHz
    0      -     74      -      6      8     66      0      -      -   3504    420
    0      -     74      -      6      8     71      0      -      -   3504    420
    0      -     74      -      6      8     70      0      -      -   3504    420
    0      -     74      -      6      8     71      0      -      -   3504    420
    0      -     74      -      6      7     63      0      -      -   3504    420
    0      -     74      -      5      7     56      0      -      -   3504    420
    0      -     74      -      6      8     70      0      -      -   3504    420
    0      -     74      -      6      8     67      0      -      -   3504    420
    0      -     74      -      6      8     69      0      -      -   3504    420
    0      -     74      -      6      8     71      0      -      -   3504    420
    0      -     74      -      6      8     68      0      -      -   3504    420

I'm trying to do streaming from a source (tv box transmitting in multicast in this source rtp://@X.X.X.X:Y) to Internet (to my mobile phone as example or another device inside of my LAN) but I can not achieve it. The command I'm using is something like this ffmpeg -i rtp://@X.X.X.X:Y -vcodec copy -f mpegts udp://127.0.0.1:1234 But it does not work as I expected, I mean, I'm able to open vlc and play the streaming in the same machine I'm running ffmpeg but not in another machine in the same LAN. Somebody can help me? Thank you! EDIT: Finally I solved installing a software called "udpxy" that forwards multicast content to the clients. I installed in a raspberry and it works perfect for this purpose. Thank you for all your explanations. It helped me to understand what I want to do and the limitations I have using a transcoder. I guess I can do the same with udpxy with ffmpeg but I can publish directly the TV Box IPs.

I'm trying to fork x11grab to no avail. m.mp4 is not generated:

ffmpeg -video_size 1024x768 \
       -framerate 25 \
       -f x11grab \
       -i :0.0+100,100 \
       /tmp/m.mp4 \
>> /tmp/l.log 2>&1 &

Only after removing the trailing ampersand & , m.mp4 is generated. Any ideas what I'm missing?

Using the drawtext filter in ffmpeg I am unable to use anything but ASCII characters. This command creates a five second test video, as expected (nothing pretty): ffmpeg -f lavfi -i testsrc -to 5 -vf "drawtext=text='ＡＴ 05 ーポン 攢ð':fontcolor=white" test.mpg But the output fails to render any non-ASCII characters: Note from left to right: ＡＴ - Double spaced characters 05 - Simple numbers ーポン - CJK characters 攢ð - AltGr + a,b,c,d in my locale (en_GB.UTF-8) At first I assumed the font was at fault, but I've checked numerous fonts and they have the relevant glyphs. Indeed my entire system has no problems with these characters at all. I then assumed it must be ffmpeg but I tried the following: convert -background black -size 800x480 -fill "#ff0080" -family "Ubuntu Mono" -pointsize 72 -gravity center label:'ＡＴ 05 ーポン 攢ð' output.png The result being: So I'm back to assuming there is something wrong with my environment. I've tried on Ubuntu Trusty and Ubuntu Xenial but the results are the same. $ locale LANG=en_GB.UTF-8 LANGUAGE=en_GB:en LC_CTYPE="en_GB.UTF-8" LC_NUMERIC="en_GB.UTF-8" LC_TIME="en_GB.UTF-8" LC_COLLATE="en_GB.UTF-8" LC_MONETARY="en_GB.UTF-8" LC_MESSAGES="en_GB.UTF-8" LC_PAPER="en_GB.UTF-8" LC_NAME="en_GB.UTF-8" LC_ADDRESS="en_GB.UTF-8" LC_TELEPHONE="en_GB.UTF-8" LC_MEASUREMENT="en_GB.UTF-8" LC_IDENTIFICATION="en_GB.UTF-8" LC_ALL= $ ffmpeg ffmpeg version 3.2.4-static http://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2017 the FFmpeg developers built with gcc 5.4.1 (Debian 5.4.1-5) 20170205 configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-5 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg libavutil 55. 34.101 / 55. 34.101 libavcodec 57. 64.101 / 57. 64.101 libavformat 57. 56.101 / 57. 56.101 libavdevice 57. 1.100 / 57. 1.100 libavfilter 6. 65.100 / 6. 65.100 libswscale 4. 2.100 / 4. 2.100 libswresample 2. 3.100 / 2. 3.100 libpostproc 54. 1.100 / 54. 1.100 $ convert -version Version: ImageMagick 6.7.7-10 2017-05-26 Q16 http://www.imagemagick.org Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC Features: OpenMP I don't know where else to look given that my locale appears to be correct, and any font I use correctly renders the font, but when passed to either ffmpeg or convert the text shown is useless. I've done the usual hours and hours of Googling to no avail. I'm amazed nobody else has seen this problem before me. Can anyone shed any light?

I'm trying to pass a command through to ffmpeg, but I'm struggling to get it to work with spaces in the name. I've tried this: filters="-vf subtitles='$filename.$format':force_style=Fontsize=24" And this: fn=$(echo $filename | sed 's: :\\ :g') filters="-vf subtitles=$fn.$format:force_style=Fontsize=24" Then ultimately executed like this: ffmpeg_command="ffmpeg -y -threads 8 -movflags +faststart $filters -pix_fmt $pfmt -c:a $acodec -c:v $codec $qualitycmd $quality $speed" echo $ffmpeg_command \"$fileout\" -i \"$filename.$format\" #Execute: $($ffmpeg_command "$fileout" -i "$filename.$format") In both of the above cases, if I do echo $filters it shows the expected result (the filename encased in ' or the spaces escaped with \) However upon execution for some reason it will fail (it will interpret the spaces in the filename as a separator for arguments and throw an error that some part of the name is not a valid argument in spite of the quotation marks or backslashes). I've confirmed the syntax should work though, if I execute it outside of a script ffmpeg -i '/path/to/Some File.mkv' -vf subtitles='/path/to/Some File.mkv':force_style=Fontsize=24 out.mp4 That works just fine, so why doesn't it in the script? And how can I work around that?

I am using ffmpeg to get the meta info of an audio clip. But I am unable to grep it. $ ffmpeg -i 01-Daemon.mp3 |grep -i Duration FFmpeg version SVN-r15261, Copyright (c) 2000-2008 Fabrice Bellard, et al. configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib --mandir=/usr/share/man --arch=i386 --extra-cflags=-O2 ... I checked, this ffmpeg output is directed to stderr. $ ffmpeg -i 01-Daemon.mp3 2> /dev/null So I think that grep is unable to read error stream to catch matching lines. How can we enable grep to read error stream? Using [nixCraft](http://www.cyberciti.biz/faq/redirecting-stderr-to-stdout/) link, I redirected standard error stream to standard output stream, then grep worked. $ ffmpeg -i 01-Daemon.mp3 2>&1 | grep -i Duration Duration: 01:15:12.33, start: 0.000000, bitrate: 64 kb/s But what if we do not want to redirect stderr to stdout?

I'm on Debian 12 & I'm using a ryzen 5600H with integrated graphics + Nvidia 1650 setup & I'm running the following command

ffmpeg -y -hwaccel cuda -i input.mp4 -vcodec libx264 -crf 24 output.mp4

But this mostly uses CPU, as I can see all of the 12 threads are getting to 100% and bloating other tasks. How can I make ffmpeg use my NVIDIA GPU mostly for this task? I have searched through various posts before, but they all seemed to be very outdated, and the ones I was able to make work destroyed the quality.