Knowledge Bits

Here I maintain "helpful notes". Little bits of knowledge which can come handy at times.

Full trace of a process under linux: strace -fFittTvs300 followed by either -p procnum or a command, and adding -o file to route the output to a file. Insert -eraw=all to see arguments pointer as adress instead of content data.

Full trace of a process under solaris: truss -faed -vall -rall -wall followed by either -p procnum or a command, and adding -o file to route the output to a file.

Full trace of a process under OpenBSD: ktrace -i followed by either -d -p procnum or a command. To watch the trace use kdump -T. If yo want to observe the process while tracing, start kdump in a separate windows and add the -l option.

Generate random password openssl passwd -table -1 `openssl rand -base64 24`

"SSL Telnet" openssl s_client -host hostname -port portnumber
see also man s_client.

Set default font for gtk 2 Put gtk-font-name="Sans 6" into .gtkrc-2.0

Quicktime Pro/iMovie encoding for the web My preferite settings for encoding my DV movies for the web using iMovie HD are:

"Movie to QuickTime Movie"
Options... Video Settings... H.264
Frame rate: current
Key frames: automatic frames
Data rate: restrict to 1000 Kbit/sec
Optimized for: Streaming
Quality Encoding:Best quality (multi-pass)
Filter...None
Size...Use current size this is 784x576 for Pal DV movies, Deinterlace
Sound Settings... Format: AAC
Channels: Stereo (L R)
Rate: 44.100 kHz
AAC Encoder Settings:Bit Rate Format: Variable Bit Rate
Taget Bit Rate: 96 - 110 kbps
Precedence: Bit Rate
Quality: Best
Prepare for Internet StreamingFast Start

with the above settings it takes about 50 minutes encoding time per minute of movie and the resulting file uses about 6 MByte per minute (approx 800 kbit/s). The following settings are used for preview movies. Encoding one minute of input takes now only 2 minutes and 1.7 MByte (approx 225 kbit/s).

"Movie to QuickTime Movie"
Options... Video Settings... H.264
Frame rate: 10
Key frames: automatic frames
Data rate: restrict to 192 Kbit/sec
Optimized for: Streaming
Quality Encoding:Best quality (multi-pass)
Filter...None
Size...196x144, Deinterlace
Sound Settings... Format: AAC
Channels: Mono
Rate: 22.050 kHz
AAC Encoder Settings:Bit Rate Format: Constant Bit Rate
Taget Bit Rate: 32 kbps
Precedence: Bit Rate
Quality: Best
Prepare for Internet StreamingFast Start

Settings I used in the past

"Movie to QuickTime Movie"
Options... Video Settings... MPEG-4 Video
Quality=Best
Frames per second: 15
Key frame every 90 frames
Limit data rate to 60 KByte/sec
Filter...None
Size...Use current size this is 720x576 for Pal DV movies
Sound Settings... MPEG-4 Audio
Rate: 44.100 kHz
Size: 16 bit
Use: Stereo
Options...Compressor: AAC (Low Complexity)
Bit rate: 32 kbits/second
Output Sample Rate: 16.000 kHz
Encoder Quality: Best
Prepare for Internet StreamingFast Start