YJL

1   Basic

mogrify -format gif input-*.png
gifsicle -d100 -O3 -k256 -l0 input-*.gif > output.gif

1.2   Using FFmpeg

With FFmpeg, it can directly output as GIF format, however, it will use dithering and that most likely wouldnt look good if you are recording a terminal window, furthermore, it will increase the file size significantly.

High quality GIF with FFmpeg explains how to generate and use a palette. In a terminal that use standard 16-color or 256-color, you can record using the following command with this palette image on the right:

ffmpeg -f x11grab -show_region 1 -r $FPS -s ${WIDTH}x${HEIGHT} \
       -i :0.0+${X},${Y} -i 256.png \
       -lavfi 'copy [x]; [x][1:v] paletteuse=dither=none' \
       output.raw.gif

The key point is the dither=none option of paletteuse filter, that will stop FFmpeg from trying to dither.

Note

paletteuse is only added since FFmpeg 2.6 (2015-03-06).

2   Trimming

If you need to trim out some frames, you can use the command as follows, which trims out the first frame (#0) and anything after the sixteenth (#15).

gifsicle output.gif '#1-15' > output.trim.gif

There is also a --delete options, it could be used like:

gifsicle output.gif --delete '#0' '#16-' > output.trim.gif

3   Rotation

gifsicle --rotate-90 output.gif > output.90.gif

There is also --rotate-180 and --rotate-270. You can also use convert from ImageMagick to do the task as seen below.

convert output.gif -rotate -90 output-90.gif

-rotate takes degree in clockwise rotation, therefore -90 is counter-clockwise for 90.

4   Last frame delay

To change last frame delay, so it wouldnt restart too fast if short delay is used in generating the GIF, you can do the following to change last frame delay to 5 seconds:

gifsicle -b output.gif -d100 '#0--2' -d500 '#-1'

# or simply

gifsicle -b output.gif -d500 '#-1'

#0--2 selects the frames between the first frame and the second last frame, and #-1 the last frame. For frame number reference, read Frame Selections in gifsicle(1).

1   Justin.tv

On Justin.tv you can grab the stream key in channel info page¹, scroll down for Stream Key.

I am not going to bore you, so here is the script I am currently using:

#!/bin/bash
# 2011-09-06T06:45:42Z

VIDEO_SIZE="630x352"
FPS="15"

STREAM_KEY="<INSERT YOU KEY HERE>"
STREAM_URL="rtmp://live.justin.tv/app/$STREAM_KEY"


/path/to/x11grabr/x11grabr -s "$VIDEO_SIZE" -r "$FPS" -bnone |
ffmpeg -f rawvideo -pix_fmt bgra -s "$VIDEO_SIZE" -r "$FPS" -i - \
       -f alsa -ac 1 -ar 11025 -i pulse \
       -vcodec libx264 -vpre baseline \
       -acodec libmp3lame -ab 32k \
       -threads 0 \
       -f flv "$STREAM_URL"
       #-f alsa -ac 2 -ar 22050 -i pulse \
       #-acodec pcm_s16le \
       #-acodec libmp3lame -ab 64k \
       #-acodec aac -strict experimental -ab 64k \
       #-acodec aac -strict experimental \

I use 630x352 because it gives me pixel-to-pixel when viewing on Justin.tv. I broadcast my desktop, so I dont like the image to be re-scaled. Also, you might want to use built-in x11grab in ffmpeg. So you may need to launch ffmpeg like (untested):

ffmpeg -f x11grab -pix_fmt bgra -s "$VIDEO_SIZE" -r "$FPS" -i :0.0 \
       # the rest of stuff

Note that I have submitted two patches, once they get released you would have better control.

servers = (
  {
    address = "livibetter.jtvirc.com";
    chatnet = "jtvme";
    port = "6667";
    password = "<YOUR JTV PASSWORD>";
    use_ssl = "no";
    ssl_verify = "no";
  }
);

chatnets = {
  jtvme = { type = "IRC"; };
};

channels = (
  { name = "#livibetter"; chatnet = "jtvme"; autojoin = "yes"; },
);

2   Ustream

As for Ustream, you need to download the FME XML file, search for <stream>, the string inside is your STREAM_KEY.

#!/bin/bash

# Go Live -> Start Broadcasting

VIDEO_SIZE="hd480"
FPS="15"

STREAM_KEY="<INSERT YOU KEY HERE>"
# flashver part is important
STREAM_URL="rtmp://1.486020.fme.ustream.tv/ustreamVideo/486020/$STREAM_KEY flashver=FMLE/3.0\20(compatible;\20FMSc/1.0)"

/path/to/x11grabr/x11grabr -s "$VIDEO_SIZE" -r "$FPS" -bnone |
ffmpeg -f rawvideo -pix_fmt bgra -s "$VIDEO_SIZE" -r "$FPS" -i - \
       -f alsa -ac 2 -ar 22050 -i pulse \
       -vcodec libx264 -vpre baseline \
       -acodec libmp3lame -ab 48k \
       -f flv "$STREAM_URL"
       # can use flv as well
       # -vcodec flv \
       #-b 1000 -vframes 500 \
       # -threads 0 \
       #-f alsa -ac 2 -ar 22050 -i pulse \
       # -acodec pcm_s16le \
       #-acodec libmp3lame -ab 32k \
       #-acodec libmp3lame -ab 64k \
       #-acodec aac -strict experimental -ab 64k \
       #-acodec aac -strict experimental -ab 32k \
       #-acodec aac -strict experimental \

3   Notes

I dont like broadcasting on Ustream, because it requires you to click on Start Broadcasting on the website and you need to keep the Flash on. Which we Linux users all know, Flash has not-so-good performance. If you know how to bypass it, please leave a comment. However, it has nice beginner controls of your stream, I think you can put on overlay text by using it.

And be careful for your stream key, ffmpeg might print out that URL, which would include your key. I think your can lower your log level, but I dont want to do that, read ffmpeg(1) if you need to.