Debating a MacBook

I’m considering a MacBook. This is about 85% motivated by my desire to try writing an iPhone app, and apparently the SDK requires a Mac. I was thinking of a Mac mini but a laptop seems to have more utility.

I’ll have to think this over for several more weeks I guess.

Oh, and Starcraft Protoss mission 7 is quite annoying.

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One-click converting .avi to .mp4 for iPod or iPhone

After a lot of searching for an easy way to do this, I stumbled onto WinFF, which is a gui wrapper around ffmpeg, a GPL’d MPEG encoder. It worked pretty well out of the box, but for all of the AVIs I’d recorded with my old camera (Canon Powershot A540) it would fail immediately with this error:

Audio resampler only works with 16 bits per sample. patch welcome.

After some searching it seems this is related to a known bug which was apparently fixed in February 2009. I set out to find a newer ffmpeg.exe (which is what WinFF calls to do the actual conversion). I found some Win32 builds of ffmpeg here but found that they all claimed to not know the “libfaac” codec. After some more digging I learned that libfaac (the audio codec for MP4 for iPod/iPhone) is no longer considered free software and was dropped from the repository in mid-April. Fortunately there were older builds available, and I grabbed the one dated 2009-04-01, extracted the ffmpeg.exe into my WinFF directory and voila, it worked.

Old ffmpeg.exe:

C:\Documents and Settings\Evan>"C:\Program Files\WinFF\ffmpeg.exe" -version
FFmpeg version SVN-r15986, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  configuration: --extra-cflags=-fno-common --enable-memalign-hack --enable-pthr
eads --enable-libmp3lame --enable-libxvid --enable-libvorbis --enable-libtheora
--enable-libspeex --enable-libfaac --enable-libgsm --enable-libx264 --enable-lib
schroedinger --enable-avisynth --enable-swscale --enable-gpl
  libavutil     49.12. 0 / 49.12. 0
  libavcodec    52. 6. 0 / 52. 6. 0
  libavformat   52.23. 1 / 52.23. 1
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 6. 1 /  0. 6. 1
  built on Dec  3 2008 01:59:37, gcc: 4.2.4
FFmpeg SVN-r15986
libavutil     49.12. 0 / 49.12. 0
libavcodec    52. 6. 0 / 52. 6. 0
libavformat   52.23. 1 / 52.23. 1
libavdevice   52. 1. 0 / 52. 1. 0
libswscale     0. 6. 1 /  0. 6. 1

New ffmpeg.exe:

C:\Documents and Settings\Evan>"C:\Program Files\WinFF\ffmpeg.exe" -version
FFmpeg version SVN-r18306, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-memalign-hack --prefix=/mingw --cross-prefix=i686-ming
w32- --cc=ccache-i686-mingw32-gcc --target-os=mingw32 --arch=i686 --cpu=i686 --e
xtra-cflags=-fno-common --enable-avisynth --enable-gpl --enable-zlib --enable-bz
lib --enable-libgsm --enable-libfaac --enable-pthreads --enable-libvorbis --enab
le-libmp3lame --enable-libopenjpeg --enable-libtheora --enable-libspeex --enable
-libxvid --enable-libfaad --enable-libschroedinger --enable-libx264
  libavutil     50. 2. 0 / 50. 2. 0
  libavcodec    52.22. 3 / 52.22. 3
  libavformat   52.32. 0 / 52.32. 0
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 7. 1 /  0. 7. 1
  built on Apr  2 2009 03:25:40, gcc: 4.2.4
FFmpeg SVN-r18306
libavutil     50. 2. 0 / 50. 2. 0
libavcodec    52.22. 3 / 52.22. 3
libavformat   52.32. 0 / 52.32. 0
libavdevice   52. 1. 0 / 52. 1. 0
libswscale     0. 7. 1 /  0. 7. 1

This also works great for encoding videos to XviD, which shrinks them to about 10-20% of their original size, making it much faster (in some cases, possible) to upload them to sharing sites.

Adventures in telephony

I’d resolved to get an iPhone a while back. It seemed to be the hands-down winner for online web browsing. My BlackBerry Pearl lost its trackball around 8 or 9 months ago and due to that experience I wanted a phone with no moving parts. I’d narrowed it down to the Nokia E71x or the iPhone. Well, I got an E71x after determining that the iPhone’s battery life to be too short.

As it turns out, AT&T added so much garbage to the E71x (as compared to the unlocked E71) that I felt like I didn’t even own it, despite paying $100 for it. There were at least two GPS-related apps that I clicked on that informed me I would be charged a monthly fee (one was $2.99 and the other $9.99 monthly) unless I went to some URL on my PC and cancelled. I attempted to delete these apps from the phone but that was apparently forbidden, even through the Nokia PC suite app. Another bother was that the inbox only showed 4 items at a time. On the E71 you can change it so that each inbox item only takes up 1 line, but on the E71x that option was missing. It was also difficult to know which connection each application was using – 802.11 or the 3G network.

Well anyway, to make a short story shorter, after one day I returned the E71x and got an iPhone.

iptables rules for rate-limiting SSH connections

This is what I use on my CentOS boxes/VMs, it rate-limits the connections and also rate-limits the log messages (to prevent attacks that attempt to fill up the server’s disk).

iptables -F
iptables -X
iptables -N LOGDROP #Create the LOGDROP chain
iptables -A LOGDROP -m limit --limit 1/s -j LOG --log-prefix "LOGDROP: " # Rate-limit the logging so the logs don't fill up the server
iptables -A LOGDROP -j DROP
iptables -I INPUT -p tcp --dport 22 -s 10.0.0.0/16 -j ACCEPT # Allow everything from the internal network
iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --set # create the "bucket"
iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --update --seconds 60 --hitcount 4 -j LOGDROP # if there are more than 4 connection attempts in 60 seconds from a given address, log-drop it.

After issuing these commands I run /etc/init.d/iptables save, that persists the rules to … somewhere. Alternatively I sometimes put all the above commands in some bash script and just call it from /etc/rc.local.