Old Black and White Movies

[bkv]

Hi

I have a few old b&w movies in mpeg2 files that I convert to DivX5 using
AutoGK. I wonder if I'm getting reaonable results or if I make the files much too small.
I have chosen 1cd as size for output file. I use DivX5 and chose the mono
option, but leave the rest to AutoGK.

I'll give you an example, and perhaps you have a comment to what I have
done ( I definetely don't understand every in and out of file conversion).
The film lasts 1 hour and 4 minutes and there is quite some flickering in parts of it. I want to see this move on my TV set.

Input mpeg2 file:
3.36 GB
Video:
Resolution 704x480
FPS 29,97
Bitrate 9363 Kbps
Quality factor 0.95 b/px
Codec : mpeg2

Output File
700 MB
Video
Resolution 400x304
Fps 23.98
Bitrate 1466 Kbps
Quality factor 0.51 b/px
Codec DivX 5.x
Audio
Channels 1
Sample rate 48000 Hz
Bitrate 61 Kbs
Codec MP3

Compressibility percentage is: 24,21. I have included the total log below

Regards,
Bjørn


[16.06.2005 23:28:18] AutoGK 1.96
[16.06.2005 23:28:18] OS: WinXP (5.1.2600).2
[16.06.2005 23:28:18] Job started.
[16.06.2005 23:28:18] Input file: spooks_run_wild.mpeg
[16.06.2005 23:28:18] Output file: C:\Documents and Settings\All Users\Dokumenter\Mine videoer\spooks_run_wild.avi
[16.06.2005 23:28:18] Audio: Audio Stream 0
[16.06.2005 23:28:18] Subtitles: none
[16.06.2005 23:28:18] Codec: DivX
[16.06.2005 23:28:18] Target size: 700Mb
[16.06.2005 23:28:18] Started encoding.
[16.06.2005 23:28:18] Demuxing and indexing.
[16.06.2005 23:32:56] Processing file: C:\Documents and Settings\All Users\Dokumenter\Mine videoer\spooks_run_wild.mpeg
[16.06.2005 23:32:57] Source aspect ratio: 4:3
[16.06.2005 23:32:57] Source resolution: 704x480
[16.06.2005 23:32:57] Found NTSC source.
[16.06.2005 23:32:57] Analyzing source.
[16.06.2005 23:37:12] Source has percentage of interlacing in motion areas: 32,64
[16.06.2005 23:37:12] Source has percentage of telecined patterns: 84,97
[16.06.2005 23:37:12] Source has percentage of progressive patterns: 15,03
[16.06.2005 23:37:12] Source has percentage of interlaced patterns: 0,00
[16.06.2005 23:37:12] Source is considered to be hybrid (mostly FILM).
[16.06.2005 23:37:13] Looking for optimal hybrid thresholds.
[16.06.2005 23:40:29] Found threshold of: 1,96
[16.06.2005 23:40:32] Output will contain 92245 frames
[16.06.2005 23:40:33] Enforcing mono audio encoding.
[16.06.2005 23:40:33] Encoding audio.
[16.06.2005 23:44:05] Audio size: 29,247,072 bytes (27.89 Mb)
[16.06.2005 23:44:05] Overhead: 5,952,768 bytes (5.68 Mb)
[16.06.2005 23:44:05] Video size: 698,803,360 bytes (666.43 Mb)
[16.06.2005 23:44:05] Target bitrate is: 1453kbps
[16.06.2005 23:44:05] Running compressibility test.
[16.06.2005 23:44:05] Writing the following script to C:\Documents and Settings\All Users\Dokumenter\Mine videoer\agk_tmp\spooks_run_wild_comptest.avs
===========================================================
LoadPlugin("C:\PROGRA~1\AutoGK\DGMPGDec\DGDecode.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\autocrop.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\decomb.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\RemoveGrain.dll")

movie = mpeg2source("C:\Documents and Settings\All Users\Dokumenter\Mine videoer\agk_tmp\spooks_run_wild.d2v")
cropclip = autocrop(movie,mode=0,wmultof=4,hmultof=4,samples=10,aspect=0,threshold=34,samplestartframe=0,leftadd=0,rightadd=0,topadd=0,bottomadd=0)
fixed_aspect = 0.909090909090909
c_width = width(cropclip)
c_height = round(height(cropclip) / fixed_aspect)
input_par = float(c_width)/float(c_height)
input_par = input_par > 1.4 ? input_par : (4.0/3.0)
out_width = 640
out_height = round(float(out_width) / input_par)
hmod = out_height - (floor(out_height / 16 ) * 16)
out_height = (hmod > 4) ? (out_height + (16 - hmod)) : (out_height - hmod)
new_aspect = (float(out_width) / float(out_height)) / fixed_aspect
Telecide(movie,order=1,guide=1,post=2).Decimate(mode=3,threshold=1.96)
autocrop(mode=0,wmultof=4,hmultof=4,samples=10,aspect=new_aspect,threshold=34,samplestartframe=0,leftadd=0,rightadd=0,topadd=0,bottomadd=0)
LanczosResize(out_width,out_height)
RemoveGrain(mode=2)
SelectRangeEvery(280,14)
===========================================================
[16.06.2005 23:51:23] Duration was: 7 minutes 1 second.
[16.06.2005 23:51:24] Speed was: 10,93 fps.
[16.06.2005 23:51:25] Compressibility percentage is: 24,21
[16.06.2005 23:51:25] Using softer resizer.
[16.06.2005 23:51:25] Chosen resolution is: 400x304 ( AR: 1,32 )
[16.06.2005 23:51:25] Predicted comptest value is: 65,64
[16.06.2005 23:51:25] Running first pass.
[16.06.2005 23:51:25] Writing the following script to C:\Documents and Settings\All Users\Dokumenter\Mine videoer\agk_tmp\spooks_run_wild_movie.avs
===========================================================
LoadPlugin("C:\PROGRA~1\AutoGK\DGMPGDec\DGDecode.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\autocrop.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\decomb.dll")
LoadPlugin("C:\PROGRA~1\AutoGK\filters\RemoveGrain.dll")

movie = mpeg2source("C:\Documents and Settings\All Users\Dokumenter\Mine videoer\agk_tmp\spooks_run_wild.d2v")
cropclip = autocrop(movie,mode=0,wmultof=4,hmultof=4,samples=10,aspect=0,threshold=34,samplestartframe=0,leftadd=0,rightadd=0,topadd=0,bottomadd=0)
fixed_aspect = 0.909090909090909
c_width = width(cropclip)
c_height = round(height(cropclip) / fixed_aspect)
input_par = float(c_width)/float(c_height)
input_par = input_par > 1.4 ? input_par : (4.0/3.0)
out_width = 400
out_height = round(float(out_width) / input_par)
hmod = out_height - (floor(out_height / 16 ) * 16)
out_height = (hmod > 4) ? (out_height + (16 - hmod)) : (out_height - hmod)
new_aspect = (float(out_width) / float(out_height)) / fixed_aspect
Telecide(movie,order=1,guide=1,post=2).Decimate(mode=3,threshold=1.96)
autocrop(mode=0,wmultof=4,hmultof=4,samples=10,aspect=new_aspect,threshold=34,samplestartframe=0,leftadd=0,rightadd=0,topadd=0,bottomadd=0)
BicubicResize(out_width,out_height,0,0.5)
RemoveGrain(mode=2)
===========================================================
[17.06.2005 00:42:49] Duration was: 51 minutes 20 seconds
[17.06.2005 00:42:50] Speed was: 29,94 fps.
[17.06.2005 00:42:51] Running second pass.
[17.06.2005 01:34:00] Duration was: 51 minutes 6 seconds
[17.06.2005 01:34:02] Speed was: 30,08 fps.
[17.06.2005 01:34:02] Job finished. Total time: 2 hours 5 minutes 44 seconds

[unskinnyboy]

We understood what you have done, but what is the question? Your issue is not clear from your post.

[E-Male]

the question is:
when you watch the result, does it look ok to you??

[bkv]

We understood what you have done, but what is the question? Your issue is not clear from your post.

Hi. Maybe I was vague, but I did state an issue :) : Have I compressed the file too much?

Let me ask one more thing: Are there any special considerations to make when converting old b&w movies whose picture may flicker and otherwise does not have a good technical quality?

[manono]

Hi-

Have I compressed the file too much?

Are you referring to the 24.21%? If so, that was the compression at the original resolution. After lowering the resolution to 400x304 and changing to a softer resizer and matrix, that compress percentage became 65%. I think that better questions might be:

1. Is the resolution too low?
2. Should I go to 2 CDs?
3. Should I use GKnot instead, or encode directly in VDubMod, in order to use the full range of filters and matrices to try and improve the final result?

As for the flickering light intensity, I've never had much luck with the available filters, although maybe someone out there is better at it than I am. To give you my opinion about the new questions:

1. Yes.
2. No, it's only a 65 minute movie.
3. Yes.

[bkv]

Thanks manono

I guess I will turn to Gordian Knot later, when I understand more of this. I don't really grasp this compressibility test, but it seems to me that the quality of the compressed movie depends om resolution and bits/pixel. Is that right?

Is it an idea to specify a minimum resolution in AutoGK? And whitch? I watch the movies on my TV-set.

[E-Male]

>>Have I compressed the file too much?
-if it does look good: no
if it doesn't: maybe

>>Are there any special considerations to make when converting old b&w movies...
-blank&white compresses better than color
BUT the old, grainy, flickering, ... material compresses extremely bad
so try some filters to denoise, but be carefull o not over-soften it
enough bitrate is a must (unless you wanna go very low with resolution, which i wouldn't)

[manono]

Hi-

The compress test is run in order to get an idea of the final quality before the 2 real passes are run. It uses (I think) 640 * xxx for the initial test. If the result is too low (as yours certainly was), then AutoGK adjusts the resolution, resizer, and matrix to get a better result. On the one hand, lowering the resolution raises the compress test result (fewer pixels to encode), but on the other hand a resolution of 400x304 will be pretty soft and blurry. The Bits/pixels thing will only go so far in helping to determine the final quality, and is useless after the compress test is run. Most 65 minute films will compress fine at a much higher resolution. But yours is old, grainy, noisy, and maybe scratched up as well, and all of those things hinder compressibility.

Personally, I wouldn't go below 512 x 384 resolution, but doing it through AutoGK may or may not give you a decent looking movie at that resolution. However, it will look better on a standard interlaced TV set than it will on the higher resolution computer monitor, and all that film grain will help cover up a lot of compression artifacts. You could experiment a bit to compare results. It only took you a couple of hours to do the movie.

[bkv]

Hi E-Male

I'll make a few experiments with these movies to learn more aboput how to compres them. File size isn't critical. I'd like to stay with the simplicity of AutoGK for a while. I'll try to set a target quality, and let AutoGK choose the file size.

[bkv]

OK so I encoded this film again. Instead of a target size of 1 CD I used target quality 75% and a minimum width of 512. I got a much smaller file, bigger resolution and much smaller bitrate. And I can't tell which one looks best.

I'll try out target quality on more files to see what I get.