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y4mcolorbars - Online in the Cloud

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This is the command y4mcolorbars that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


y4mcolorbars - Create a YUV4MPEG2 stream containing a colorbar test pattern

SYNOPSIS


y4mcolorbars [options]

DESCRIPTION


y4mcolorbars creates a YUV4MPEG2 stream consisting entirely of frames containing a
colorbar test pattern. The pattern attempts to reproduce the standard SMPTE EG-1-1990
colorbar test signal as faithfully as possible, given the constraints of the Y'CbCr
colorspace.

Output is to stdout to facilitate piping to other MJPEG tools.

OPTIONS


y4mcolorbars accepts the following options:

-n num
Output a total of 'num' output frames. [default: 1]

-F n:d
Set framerate encoded in output stream, as an exact integer ratio. Common rates are:
24000:1001 - NTSC 3:2 pulldown converted film
24:1 - native film
25:1 - PAL/SECAM
30000:1001 - NTSC video [default]
50:1 - PAL field rate
60000:1001 - NTSC field rate

-W w Set frame width. [default: 720]

-H h Set frame height. [default: 480]

-A n:d
Set pixel aspect ratio encoded in output stream, as an exact integer ratio. Common
ratios are:
1:1 - square pixels (e.g. computer graphics)
10:11 - CCIR-601 NTSC [default]
59:54 - CCIR-601 PAL

-I x Set interlacing mode, used to interpret the PPM image(s), and also encoded in output
stream.
p - progressive, non-interlaced [default]
t - top/upper-field-first interlaced
b - bottom/lower-field-first interlaced

-Q n Data to place in the "-I/+Q" patches in the bottom row of the pattern:
0 - -I and +Q at 20% (20IRE) [default]
1 - -I and +Q at 50% (50IRE)
2 - +Cb and +Cr at 100%

-S mode
Set chroma subsampling mode.
444 - 4:4:4 (no subsampling) [default]
420jpeg - 4:2:0 JPEG/MPEG-1, interstitial cositing
420mpeg2 - 4:2:0 MPEG-2, horizontal cositing

The supported subsampled modes use a lousy subsampling filter; better results will be
achieved by passing the default 4:4:4 output to a scaler which supports subsampling,
such as y4mscaler(1).

-v [0,1,2]
Set verbosity level.
0 - warnings and errors only.
1 - add informative messages, too. [default]
2 - add chatty debugging message, too.

EXAMPLES


To create and display 200 frames of colorbars corresponding to a top-field-first
interlaced 4:3 NTSC source:

y4mcolorbars -n 200 -It -S 420jpeg | yuvplay

To create and display 200 frames of colorbars corresponding to a bottom-field-first
interlaced 4:3 PAL source:

y4mcolorbars -n 200 -H 576 -F 25:1 -A 59:54 -Ib | yuvplay

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