Spartan's world

Deinterlacing with Mencoder

2009-01-09T15:28:00.000-08:00

Here's some more of those Command Line Beauties that I keep forgetting. The funny thing is people at the Computer Vision Lab always do these stuffs with Adobe Premiere, they lose out in the fun game.

#Getting information from a video file

$ mplayer -identify part11.avi
...
ID_VIDEO_ID=0
[aviheader] Video stream found, -vid 0
AVI: No audio stream found -> no sound.
VIDEO: [FMP4] 1922x1188 24bpp 24.000 fps 875.3 kbps (106.9 kbyte/s)
Clip info:
Software: MEncoder 2:1.0~rc2-0ubuntu13.1
ID_CLIP_INFO_NAME0=Software
ID_CLIP_INFO_VALUE0=MEncoder 2:1.0~rc2-0ubuntu13.1
ID_CLIP_INFO_N=1
ID_FILENAME=part11.avi
ID_DEMUXER=avi
ID_VIDEO_FORMAT=FMP4
ID_VIDEO_BITRATE=875344
ID_VIDEO_WIDTH=1922
ID_VIDEO_HEIGHT=1188
ID_VIDEO_FPS=24.000
ID_VIDEO_ASPECT=0.0000
ID_LENGTH=41.62
...

# Deinterlacing an already interlaced video
$ mencoder -ovc lavc -lavcopts vbitrate=3000 -vf lavcdeint -ofps 24000/1001 0002.avi -o 0002new.avi

# Converting a set of JPG files to an AVI video
$ mencoder mf://*.jpg -mf w=800:h=600:fps=24:type=jpg -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:trell -oac copy -o part11.avi

I would post more of these in the next post. It feels great to be recognized for command-line skills.

tovid : A tool for the intrepid DVD publisher

2008-03-24T03:40:00.000-07:00

For weeks a friend of mine, Santosh had been requesting me to write a DVD for him that would contain some of his dance steps and a few of his favorite moments from the cultural event of his office. After trying various tools like - manDVD, qDVDauthor and tovidGUI; I tried the command line version of tovid. To much of my surprise - it was not that nasty as it looked like in the beginning.

Here are some of the drawbacks of the previous tools I have tried and failed in some step or the other.
a) manDVD - Interface is too blunt. No matter how well you have encoded a video, it would still re-encode it. Thats unnecessary and indeed wastes a lot of time.

b) qDVDauthor - Again the interface is too blunt. For no reason, perfect mpg files encoded in a particular bitrate could not be included in the menu structure. Does not work for multimedia content in vfat filesystems. Cannot burn dvd - keeps saying /dev/cdrom (regardless of whatever path put) not found.

c) tovidgui - Does not work for vfat file-systems.

This is what I used to create my DVD menu from the following mpg files :
1.mpg 2.mpg 3.mpg 4.mpg 5.mpg 6.mpg 7.mpg

The menu background image was specified with the -background option and the audio playing in the background was specified by -bgaudio option. The -pal option makes the DVD compatible with TV signals inputs acceptable in most of the Asian countries. Finally the directory where the DVD directory structure is to be copied. Its better to have this directory on an ext3 filesystem.

$ todisc -pal -files 1.mpg 2.mpg 3.mpg 4.mpg 5.mpg 6.mpg 7.mpg \
-titles "Introduction" "Nache mahiya" "Duet performance" "Guitar" "Its rocking" "Tapanku song" "Santosh exclusive" \
-menu-title "Umang 2007/2008" -menu-fade -menu-font Airmole -menu-fontsize 40 \
-title-color '#2e9900' -stroke-color lightgray -thumb-font Airmole -thumb-fontsize 20 \
-thumb-text-color '#2e9900' -showcase -background bgimg.png -bgaudio bg.mp3 \
-showcase-titles-align west -text-mist -text-mist-color gray85 -text-mist-opacity 70 \
-out /opt/movies/dvd-burn

Something that truck me after I had created the DVD (still not burned it to the DVD media) was - if everything was alright. One of the things that should be checked out is - if all the menu buttons were behaving as they were supposed to. gxine is a good alternative in this regard.

$ apt-get install gxine gxineplugin

is enough for my Debian etch 4 to install the needful. Once gxine is properly installed - the DVD contents could be tested with the following:

$gxine dvd:///opt/movies/dvd-burn

If everything is alright, the menu buttons could be clicked through a virtual keypad interface provided with the gxine player. Through view->keypad, one could navigate through the various menu items.

Secondly my home DVD player has limited capabilities as per as decoding audio is concerned. I know that audio encoded in AC3 could be decoded by my DVD player. Some of the files contained audio encoded in some format alien to my player mp3lib. I figured that out when I played the files from my command line mplayer.

AUDIO: 48000 Hz, 2 ch, s16le, 224.0 kbit/14.58% (ratio: 28000->192000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)

Other files containing audio that are well recognized by my player spit something like this when run through mplayer :

AUDIO: 48000 Hz, 2 ch, s16le, 224.0 kbit/14.58% (ratio: 28000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)

So I had to ensure that those files (encoded using mp3lib) get converted into AC3 codec supplied by liba52. mencoder comes handy here :

$ nice -n 0 mencoder -oac lavc -lavcopts acodec=ac3:abitrate=224 -ovc copy -o 4.test.mpg 4.mpg

This is what I got as output when I ran mplayer:

AUDIO: 48000 Hz, 2 ch, s16le, 224.0 kbit/14.58% (ratio: 28000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)

After everything looks fine, burning the DVD is what I require and makedvd is the appropriate too:

$ makdvd -burn /opt/movies/dvd-burn

Thats it. I could play it in my TV with my DVD player. I was happy and so was Santosh. Now wasn't it a piece of cake?

Fiddling with movie DVDs

2008-03-07T23:40:00.000-08:00

With the advent of the cheap DVDs, movie viewing has become an experience as pleasant as never before. In a country where I live, I get DVDs that contain high quality movies (sometimes more than 3) on a single disk. Amazing isn't it? I had always wondered how I could create one like that. Technology/software isn't a challenge - though finding time among weekends, is. The objective of this post to guide myself as well as others when such requirements arise:

a) People who are oblivious to the fact that DVDs could be ripped into desired container file formats (avi, mpeg, matroska etc.) through a plethora of available codecs often copy the vob files directly from their DVDs to the computer's disk. Apparently there isn't anything wrong with that but it could only be played in computer. Also, the files couldn't be written as they are into DVDs for reading in a DVD player.

I use the following mencoder commands to rip a VCD/DVD into an avi file:

$ mencoder vcd:// -ss -endpos -oac mp3lame -ovc xvid -xvidencopts pass=1 -o /dev/null

$ mencoder vcd:// -ss -endpos -oac mp3lame -ovc xvid -xvidencopts pass=2:bitrate=800 -o

Where -ss : Starting position in terms of seconds
-endpos : Ending positions in terms of seconds
bitrate could be increased to increase resolution - but then it increases file size as well

And the following command to convert vob files copied directly from DVDs to mpeg files:

$ mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf -vf scale=720:480,harddup \
-srate 48000 -af lavcresample=48000 -lavcopts \ vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=5000:vbitrate=3000:keyint=18:vstrict=0:acodec=ac3:abitrate=192:aspect=16/9 -ofps 30000/1001 -o

The more the vbitrate and vrc_maxrate values you input, the better resolution the conversion would result in.

b) Joining multiple avi files too is a piece of cake with mencoder. All I had to do is :

$ mencoder -ovc copy -oac copy -o <1st-part.avi> <2nd-part.avi> <3rd-part.avi>

There are many of these tips and tricks that I am sure many would find handy. I am planning to append a few more lines in this post to make it as useful as possible.

For further reference you could look into :

http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-vcd-dvd.html

[/proc/cpuinfo] How many brains do I have?

2006-10-25T23:30:00.000-07:00

The title has a strange question. Isn't it an obvious one? All human beings indeed have only one brain. Computers do have brains in the form of CPUs. I happened to lurk into this file /proc/cpuinfo in my unix system. It has a lot of interesting stuffs.

It was intriguing to find how many processors my machine has. The answer to the question lies on how many entries do I have. All the processors and their respective informations are tabulated under lines like this:
processor: 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) 4 CPU 3.20GHz
stepping : 1
cpu MHz : 3192.773
cache size : 1024 KB
...
...
...

processor: 1
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) 4 CPU 3.20GHz
stepping : 1
cpu MHz : 3192.773
cache size : 1024 KB
...
...

'Grep'ing through various google pages, I gathered a finer detail. The above system could have two physical processors or a virtual processor on top a physical processor. Such a case is observed when the CPU has HYPERTHREADING(HT) or SYMMETRIC MULTI-THREADING(SMT) support available. The operating system needs to be installed with a knowledge of such processor features.

Following lines in the /.config configures SMP support for a Linux kernel.
CONFIG_SMP=y
CONFIG_X86_FIND_SMP_CONFIG=y
CONFIG_X86_SMP=y

Plethora of information is provided with the CPU flags section. Presence of an ht flag elucidates HYPERTHREADING capabilty of the processor to which the flags are associated. What if the system has another physical processor together? Another flag lm advocates for it.

The machine I use has these flags.
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr
Since there is no lm flag here, it only has one physical CPU and hence only one brain. However since the CPU has SMT capability, two processors are observed.

In laymen terms SMT/HT makes the machine look more intelligent!

[init 1] Its Just me

2006-08-03T06:08:00.000-07:00

After years of pondering on why on earth does anybody need a blog and if I should need one, I have found a reason to start blogging. My late hours of stay in office doesn't let me spend enough time with my diary which I have been using all these years to pen down my thoughts. To write a blog I don't need any special preparation. Not even a pen!

Just half an hour at the end of a triring day is fine. Now that was all about jotting down the thoughts, is it necessary to publish it? The answer varies from individual to individual. When it comes to me, its definitely yes. The journal of my life doesn't log the activities that I simply do everyday, but it depicts a certain lesson that I learnt from them. The lesson I learnt today could be incomplete, but thats when I see it today. Tomorrow or the day after who knows, it could get complete. As I believe strongly in open source, a lot of what I have learnt all these years could be beneficial for the community that thrives for knowledge. Hence this post finds a place here.

Now a short note about the subject:
[init 1] is command in Unix based systems that brings the system to a single-user mode. Since this is my first post, it is very unlikely that it will be about something/someone other than only me.