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HelpUpdate : README.video.codec - ascii banner ! + some extra love

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Jerome Blanchi aka d.j.a.y
2019-07-02 20:23:32 +02:00
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veejay-current/veejay-server/doc/README.video-codec.md
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Video files Video files
========================= =========================
Basic knowledge 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. [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: ### Floss tools that support MJPEG:
* [Cinelerra](http://cinelerra.org/) - Video editing and compositing software * [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 ? Which resolutions to use ?
------------ ------------
Veejay can do: Veejay can do:
* high resolutions aka HDTV * high resolutions aka HDTV
* pal 16/9 : 1024x576 * pal 16/9 : 1024x576
* pal: 720x576 * pal: 720x576
@@ -64,31 +80,39 @@ How to convert ?
------------- -------------
### You can use FFMpeg ### 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. 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. 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 -c:v mjpeg -s 720p -r 25 -pix_fmt yuvj422p -acodec pcm_s16le -ar 44100 -ac 2 output-file.avi $ 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. Check FFmpeg documentation for detailed description of transcoding process and possible customization/automation.
### Or, you can use mplayer ### Or, you can use mplayer
``` ```shell
$ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -o <outputfile> <inputfile> $ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -o <outputfile> <inputfile>
``` ```
***To scale on the fly, use*** ***To scale on the fly, use***
``` ```shell
$ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -vf scale=352:288 -o <outputfile> <inputfile> $ mencoder -ovc lavc -oac pcm -lavcopts vcodec=mjpeg -vf scale=352:288 -o <outputfile> <inputfile>
``` ```
***Bulk encoding*** ***Bulk encoding***
A quick hint for bulk encoding a bunch of capture.dv files 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; $ 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 Going deeper in videos
------------ ------------
### What is Dummy mode ? ### What is Dummy mode ?
``` ```shell
$ veejay -d $ 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). 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) 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)
``` ```shell
$ sudo modprobe v4l2loopback # modprobe v4l2loopback
$ ffmpeg -f x11grab -r 25 -s 720x576 -i :0.0+5,10 -vcodec rawvideo -pix_fmt yuv422p -f v4l2 /dev/video0 $ ffmpeg -f x11grab -r 25 -s 720x576 -i :0.0+5,10 -vcodec rawvideo -pix_fmt yuv422p -f v4l2 /dev/video0
$ veejay -A1 -a0 $ veejay -A1 -a0
``` ```