Automated Cutting and Transcoding Guide Using Mencoder

[Deusxmachina]

Things look clean from your attachment. Maybe the PC really is haunted...

Have you tried a build from here?

http://oss.netfarm.it/mplayer-win32.php

I couldn't tell what the difference between some of those builds are, so so far I tried the P4 one with my C2D along with some holy water and changing my motherboard to a Ouija board.

Good news: mencoder doesn't quit and does run through the file. Bad news is the file has a terrible stutter. But only for an h.264 .mkv. It looks fine on the quick h.264 .mp4 clip I just made.

Still weird, but close!

[-stattik-]

Good to hear. I don't think the mkv and mp4 containers are completely compliant, especially with B-frames.

[Deusxmachina]

Good to hear. I don't think the mkv and mp4 containers are completely compliant, especially with B-frames.

You mean just with this particular script, or what? mkv and mp4 are the only things that are fully compliant with h.264.

[-stattik-]

I was talking about mencoder. Directshow doesn't seem to like the mkv/mp4 files it creates. I currently mux into an avi container and use Haali Media Splitter to view them in GBPVR.

[erik]

Not sure if mencoder can use the information but the newest release of Comskip can generate a aspect ratio information file.
Maybe this is of use to automaticall crop the picture for more efficient encoding.
Example of output:

Code:

0:00:00.03 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:00:04.83 1920x1088 2.20 minX=   1, minY=  98, maxX=1920, maxY= 990
0:00:45.44 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:03:43.08 1920x1088 2.32 minX=   1, minY= 130, maxX=1920, maxY= 958
0:04:08.91 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:04:38.94 1920x1088 2.20 minX=   1, minY= 114, maxX=1920, maxY= 982
0:05:24.02 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:05:39.03 1920x1088 2.91 minX=   1, minY= 218, maxX=1920, maxY= 878
0:05:56.38 1920x1088 2.60 minX=   1, minY= 178, maxX=1920, maxY= 918
0:06:09.03 1280x 720 1.36 minX= 154, minY=   1, maxX=1126, maxY= 720
0:07:09.26 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:07:19.37 1920x1088 2.08 minX=   1, minY=  82, maxX=1920, maxY=1006
0:07:23.94 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:21:02.16 1920x1088 2.20 minX=   1, minY= 106, maxX=1920, maxY= 982
0:21:32.09 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:23:06.01 1920x1088 2.20 minX=   1, minY= 106, maxX=1920, maxY= 982
0:23:32.04 1280x 720 1.36 minX= 154, minY=   1, maxX=1126, maxY= 720
0:24:32.07 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088

[-stattik-]

Not sure if mencoder can use the information but the newest release of Comskip can generate a aspect ratio information file.
Maybe this is of use to automaticall crop the picture for more efficient encoding.
Example of output:

Code:

0:00:00.03 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:00:04.83 1920x1088 2.20 minX=   1, minY=  98, maxX=1920, maxY= 990
0:00:45.44 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:03:43.08 1920x1088 2.32 minX=   1, minY= 130, maxX=1920, maxY= 958
0:04:08.91 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:04:38.94 1920x1088 2.20 minX=   1, minY= 114, maxX=1920, maxY= 982
0:05:24.02 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:05:39.03 1920x1088 2.91 minX=   1, minY= 218, maxX=1920, maxY= 878
0:05:56.38 1920x1088 2.60 minX=   1, minY= 178, maxX=1920, maxY= 918
0:06:09.03 1280x 720 1.36 minX= 154, minY=   1, maxX=1126, maxY= 720
0:07:09.26 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:07:19.37 1920x1088 2.08 minX=   1, minY=  82, maxX=1920, maxY=1006
0:07:23.94 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:21:02.16 1920x1088 2.20 minX=   1, minY= 106, maxX=1920, maxY= 982
0:21:32.09 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088
0:23:06.01 1920x1088 2.20 minX=   1, minY= 106, maxX=1920, maxY= 982
0:23:32.04 1280x 720 1.36 minX= 154, minY=   1, maxX=1126, maxY= 720
0:24:32.07 1920x1088 1.77 minX=   1, minY=   1, maxX=1920, maxY=1088

Interesting. So comskip detects the aspect ratio and figures out the actual resolution and offset needed for the optimal crop. Does comskip list the dominant resolution and offset?

[erik]

Interesting. So comskip detects the aspect ratio and figures out the actual resolution and offset needed for the optimal crop. Does comskip list the dominant resolution and offset?

Comskip lists the actual resolution of the input file and the area with active video. This active video area is measured with a rather complex algorithm.
The minx,maxx,miny,maxy are the boundaries of the active video. the aspect ratio is calculated from the active video.
So the output contains per line

• start time of segment
  
• encoded resolution of input video
  
• aspect ratio calculated from active video area
  
• coordinates of the active video area.
  

And there are MANY more possibilities being broadcasted then only 16/9 or 4/3 inside 16/9 or 4/3

Combined with the .edl file you should be able to determine the correct crop area for the show being transcoded

[Questor]

Hello stattik and Erik,

I've run through some info on comskip, comskip and comcut as well as stattik's transcode batch file.

I've also checked some google searches and so forth trying to answer my question but no luck so far.

Here are the questions:
a. Why does comskip produce a text file with shaded text/graphics accurately displaying the logo for a given station (extracted by frame comparison from the mpeg file)

b. What other programs use this logo file, and in what ways?

c. I have not found a way of using the transcode.bat file to use this logo file in any way, as I would like to remove the logo from the mpeg file.

I have found several sites describing methods of grabbing a frame of video, editing just the area that contains the logo, and supplying it as a filter to various editing tools such as virtualdub and another for using mencoder, but neither of these mention a text logo representation.

I have also found a recently released (3/20/08) Australian utility (Translogo) that identifies the logo in one pass and then has a utility for specifically removing it. (Apparently ABC is now adding large colored logos to Aussie channels)

However if the logo is already being identified by comskip, and mencode is already being used to remove the comercials with comskip input file, and there exists a method of masking it out with mencoder why the three couldn't be combined in the transcode batch.

Erik,
- regarding your recent post and how the program identifies the borders of active video,
does this calculation take into account the presence (or absence) of the logo?
I ask because I was transcoding an IFC channel video which was displayed in letterbox format, and maybe 1/4 to 1/6 of the logo was actually over the video and the rest was over the black bar widescreen area. So if the logo could effectively be ignored comskip would show widescreen dimentions.

[-stattik-]

mencoder does have a method to remove logo's but it's not automated. You must manually specify where the logo is located. This script doesn't use it. Info can be found here:

http://www.mplayerhq.hu/DOCS/man/en/mplayer.1.html

Search for "delogo."

[-stattik-]

Here's 0.5.6. The biggest differences are new quality profiles and the ability to use mkvmerge to mux into the mkv container. This will probably be one of the final versions of the script, not including the inevitable bugfixes since it should do just about everything I need it to do. Please test it out and post your feedback.

0.5.6
* Added simple quality profiles. Now using Guided Transcode, you can select from three qualities. You may also change the quality profiles or assign certain shows to certain profiles automatically.
* mkv container support via mkvmerge.exe is supported. This will create Direct Show compatible MKV files. mkvmerge.exe is part of MKVtoolnix and can be found here: http://www.bunkus.org/videotools/mkvtoolnix/ When enabled, the script creates an avi with a mkv extension (for database renaming purposes) and then uses mkvmerge.exe to remux it into a mkv container.
* Fixed a bug when moving a file that's larger that the move directory.
* Adjusted the pillarbox crop. The previous setting left a little black bar on each side.

0.5.5c
* Added vmq patches for cropping, full resolution, and accepting files with "&" or "^" in their names.
* Removed old PSP profile.
* Subtitles will be added if corresponding .srt file is found.
* Adjusted the x264 encoding parameters. It's slight slower but with better quality.
* This version is using a better IVTC method for 60FPS material.