From 86fc0b5e450f057117941329f38e1fa3a241e385 Mon Sep 17 00:00:00 2001 From: "Jerome Blanchi aka d.j.a.y" Date: Tue, 2 Jul 2019 20:23:32 +0200 Subject: [PATCH] HelpUpdate : README.video.codec - ascii banner ! + some extra love --- .../veejay-server/doc/README.video-codec.md | 48 ++++++++++++++----- 1 file changed, 36 insertions(+), 12 deletions(-) diff --git a/veejay-current/veejay-server/doc/README.video-codec.md b/veejay-current/veejay-server/doc/README.video-codec.md index b1886dd6..c744cd32 100644 --- a/veejay-current/veejay-server/doc/README.video-codec.md +++ b/veejay-current/veejay-server/doc/README.video-codec.md @@ -1,3 +1,15 @@ + + __ __ ____ ___ ___ ___ __ ___ ___ ___ __ + | | || || \ / _] / \ / ] / \ | \ / _] / ] + | | | | | | \ / [_ | | / / | || \ / [_ / / + | | | | | | D || _]| O | / / | O || D || _] / / + | : | | | | || [_ | |/ \_ | || || [_ / \_ + \ / | | | || || |\ || || || |\ | + \_/ |____||_____||_____| \___/ \____| \___/ |_____||_____| \____| + + + + Video files ========================= Basic knowledge @@ -30,7 +42,10 @@ so... Which codec to use ? ------------- [MotionJPEG](https://en.wikipedia.org/wiki/Motion_JPEG) (mjpeg) is the veejay codec of choice for most applications, it gives you a good tradeof between compression, quality and compatibility. M-JPEG is an intraframe-only compression, each video frame is coded separately as a JPEG image, giving advantage of rapidly changing motion in the video stream. -If you ever want more speed, use AVI `yv16` or `i420` before recording to new samples. Either using console client and **sayVIMS** (`selector 302` _Set codec to use for recording_) or the gui client **Reloaded** [Sample/Stream panel] ---> [Recording to Disk panel] ---> [Codec drop down list]. +If you ever want more speed, use AVI `yv16` or `i420` before recording to new samples : + +* using console client and **sayVIMS** (`selector 302` _Set codec to use for recording_ (use 'x' to see list)) +* from gui client **reloaded** [Sample/Stream panel] ---> [Recording to Disk panel] ---> [Codec drop down list]. ### Floss tools that support MJPEG: * [Cinelerra](http://cinelerra.org/) - Video editing and compositing software @@ -49,6 +64,7 @@ If you ever want more speed, use AVI `yv16` or `i420` before recording to new sa Which resolutions to use ? ------------ Veejay can do: + * high resolutions aka HDTV * pal 16/9 : 1024x576 * pal: 720x576 @@ -64,31 +80,39 @@ How to convert ? ------------- ### You can use FFMpeg +```shell +$ ffmpeg -i input-file -c:v mjpeg -pix_fmt yuvj422p -q:v 1 -an output-file.avi ``` -$ ffmpeg -i input-file -c:v mjpeg -pix_fmt yuvj422p -q:v 0 -an output-file.avi -``` +Your input video `input-file` will be transcode to `mjpeg` video codec, with a pixel +format `yuvj422p` - color values from 0-255 and only horizontal chroma resolution is halved. +For better performance (but less image accuracy...) you can choose `yuvj420p` , in that +case, both horizontal and vertical chroma resolution are halved. Finally it use a +video quantifier of `1` setting the quality scale (VBR) to best image quality. + In previous example, audio is muted using the `-an` flag, consequently you would start **veejay** with `-a0` to disable audio. -Optionally add PCM 16bit audio, 44.1/48.0 Khz, 2 channels, 8 bits per channel, HD resolution and 25 frames per second. -``` -$ ffmpeg -i input-file -c:v mjpeg -s 720p -r 25 -pix_fmt yuvj422p -acodec pcm_s16le -ar 44100 -ac 2 output-file.avi +Optionally add PCM WAVE 16bit audio, 48.0 Khz, 2 channels, 8 bits per channel, HD resolution and 25 frames per second. +```shell +$ ffmpeg -i input-file -q:v 1 -c:v mjpeg -s 720p -r 25 -pix_fmt yuvj422p -acodec pcm_s16le -ar 48000 -ac 2 output-file.avi ``` +For more detailled informations concerning audio, look at `README.audio.md` + Check FFmpeg documentation for detailed description of transcoding process and possible customization/automation. ### Or, you can use mplayer -``` +```shell $ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -o ``` ***To scale on the fly, use*** -``` +```shell $ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -vf scale=352:288 -o ``` ***Bulk encoding*** A quick hint for bulk encoding a bunch of capture.dv files -``` +```shell $ for i in `ls *dv`;do mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -o `echo $i | sed s/.dv/.avi/` $i; done; ``` @@ -97,7 +121,7 @@ Consult mplayer documentation about other options, such as cropping and filterin Going deeper in videos ------------ ### What is Dummy mode ? -``` +```shell $ veejay -d ``` @@ -111,8 +135,8 @@ If you use a video file, veejay will take that file's properties as default sett You can create a fake v4l2 device (`/dev/videoX`), using [v42loopback](https://github.com/umlaeute/v4l2loopback). Setup a single virtual video device on `/dev/video0` (assuming that it does not previously exist), stream some screen capture to it and open veejay using this source (audio disabled) -``` -$ sudo modprobe v4l2loopback +```shell +# modprobe v4l2loopback $ ffmpeg -f x11grab -r 25 -s 720x576 -i :0.0+5,10 -vcodec rawvideo -pix_fmt yuv422p -f v4l2 /dev/video0 $ veejay -A1 -a0 ```