Recording Questions--Use of Multiple Passes

Discussion in 'CloneDVD mobile' started by maclen, Jan 7, 2008.

  1. maclen

    maclen Member

    KnoWei and Others,

    You are obviously very knowledgable and have helped me optimize my settings. I have an Archos 705. I was informed by Slysoft that even though there is no setting at present for the 705, I should use the 605 settings. I have a few questions and observations:

    1. I always checked the deinterlace option (since it is a default setting) but I found that on DVDs, it was not necessary and increased the file size, or in other words, prevented me from using a higher quality setting.

    2. The Archos manual actually says that all types of formats (except the avi format) cannot exceed 4gbs per file. For avi formats, one cannot exceed 2gbs. Until I found that out, I couldn't figure out why my movies couldn't play when the file was larger than 2gbs.

    3. I'm not sure about the effectiveness of the 2 pass option (or for that matter the 3 pass option which I've never tried). For one, when I use the maximum resoultion on one pass, the time it takes to rip is at least 75 minutes for about a 2 hour movie. When I select the 2 pass option, it takes another 75 or more minutes. I have actually found that the 2nd pass takes longer than the 1st. Does anyone know why?

    4. Interestingly, when I rip an avi file with only 1 pass, I notice that the fps is 29. However, when I use 2 passes, it is reduced to 23 fps. I'm not sure why this happens, which brings me to my other question. I had thought that prior pmps or pvps showed jerky and unacceptable films because they only could play 15fps, and I thought that one of the greatest improvements in new pmps or pvps was that they could play 30 fps. So, isn't 23fps actually degrading the quality of the video?

    4. Sorry, last question. One DVD that was originally a TV show I ripped using these settings and there were horizontal lines and jerkiness of the scenes when I played it back. Is this because the DVD was originally recorded for TV? Also, is this a situation that calls for deinterlacing checked to correct these problems?

    Many thanks for your answers.
     
  2. KnoWei

    KnoWei Well-Known Member

    I agree many others are very knowledgeable. I'm just learning on the job. However since you've included me with such great company I'll take a stab at your questions. :D

    For movies (vs. TV shows) it is my experience you should *not* check the Deinterlace box. In addition to the impacts you mentioned you will get some subtle artifacts in the movie. In particular around sharp reflective horizontal lines in the video. For example a person in a plaid sports coat will look like they are wearing a neon sign. Long edges like that of a shiny table will have a tendency to shimmer and move too.

    Search this forum and on google for OpenDML or odml to learn more about the 2GB file limitation on the avi container. It was one of the first things I tripped across and learned to overcome because I wanted bigger files. The solution may or may not work on your player. Or it may work partially for example the file may play but you might not be able to use FF or Seek functions after a certain point in time.

    2 pass is effective for creating better quality videos. 3 pass probably does not get you enough more to be worth the processing time. However if you are watching on a smaller (hand-held) screen the difference between 1 and 2 pass might not be noticable. Also if the source is rather unvarying (Talkshow vs. Action/Thriller) it probably won't be noticable. Peer has explained this elsewhere in the forum. Also a lot written about it elsewhere. The (very) basics are that the 1st pass is like a test run so the encoder knows how to make the most efficient use of the available data bits during the second pass. Rapid changes require more bits. Stretches of low change require fewer bits. But there's a finite number of bits that can be used for a particular video file.

    Sounds like a dual core processor and 2GB of RAM. Probably about typical time for that set up. Am I right? Search on "threads=" in this forum if you have a multi-core processer. It speeds things up some. Also monitor your CPU to see if it's maxing out during conversion. If so try to stop non-essential processes and applications.

    Yes, each pass is essentially a full conversion of the video. The second one taking longer is probably because the first one is a test run and the second is the actual conversion and write to disk. Perhaps someone else who has measured this will comment.

    Out of my depth completely and have not attempted to check this sort of thing before. Although I would have thought that players would not be sensitve to frames per second as long as the fps was valid for the file type. I would have thought that they would be more sensitive to the data rate which is given in kilobits per second (kbps). This [bit rate] is configured in the Devices.ini file for the particular device profile.

    Without having personally tested this I'm going to say "yes" - that's what DeInterlacing is for. There are some good web sources on this topic. Recommend googling for it. Wikipedia has some stuff and there's some in these forums as well.

    Hope they help.

    ~KnoWei
     
    Last edited: Jan 8, 2008
  3. profcolli

    profcolli Well-Known Member

    Not necessary unless the DVD uses VIDEO source material (e.g. TV season disks).
    Just out of interest, why would you want such a large file for a handheld player? A 1.5 hour movie in DivX format at the 1000kbps assumed by Archos in their promos (using 720x480) should be a fraction of that size (~1GB).
    Without knowing your system it is hard to comment. However, your encoding times will be shorter if you don't use the highest settings and/or with one pass encoding. The quality difference from the extra passes may be obvious on a large screen, but seeing any difference on a 7" handheld is beyond the capabilities of my eyes - YMMV.
    Is this for the same material? Short answer - no need to worry.
    Long answer - 30fps is video based material. 24fps is film (movies are shot at 23.976fps) - pulldown detection (which improves the quality of the video) will see the source. Not all DVD's correctly identify this (3:2 pulldown) so 30fps may be used (29.97fps actually). Here's a quick guide:
    http://en.wikipedia.org/wiki/24p
    Correct - see response to 1 above. On the screen where that option appears, click on the question mark at the top of the screen then click on the option - you will see a popup explaining that.

    EDIT: I see that you posted this question in another thread also.
    For anyone interested KnoWei has responded there:
    http://forum.slysoft.com/showpost.php?p=78847&postcount=12
     
    Last edited: Jan 8, 2008
  4. maclen

    maclen Member

    KnoWei,

    Thanks very much for your thoughtful and quick response.

    The 2gig limitation for avi files is a restriction that appears in the Archos manual and appears to be a limitation of the player.

    The Archos 705 has a very large screen (7" diagonally) so perhaps the 2 pass is necessary. However, in comparing two movies (one done with 1 pass and the other with 2), I didn't notice any discernable difference.

    I appreciate your suggestions about speeding up the processing time.

    Thanks again. Your post helped a lot.
     
  5. maclen

    maclen Member

    profcolli,

    I appreciate your quick and intelligent responses.

    Regarding your question about the size of the files, my player has 160gigs, and I bought it solely to record videos. In experimenting with various settings, I have found that when I use a 1500 or higher bit rate, the quality is noticeably better. As time goes on, I may regret this decision and have to reduce the file size.

    I responded to KnoWei the same way. I have tried all kinds of videos using a high bitrate but with one or two passes, and I really can't tell the difference with 2 passes. Since the second pass adds another hour or more to the processing time, I may just use the one pass setting. (Could it be that the higher bitrate offsets the multiple passes? Or am I mixing apples and oranges?)

    Thanks for the information and the link about fps. The two different readings I got (29 fps and 23 fps) were on two film DVDs. I couldn't account for the difference in the speeds.

    Sorry about posting in another thread. I didn't think my post went through, so I posted here. Many thanks again.
     
    Last edited: Jan 8, 2008
  6. KnoWei

    KnoWei Well-Known Member

    I believe Archos is indirectly saying that the player doesn't supoprt the OpenDML extension. The original AVI spec, as I've researched it, is limited to 2GB. However I would test that on your player as it may play odml extended AVI files greater than 2GB. You can try the options from the appropriate config in this sticky for Devices.ini modifications.
    http://forum.slysoft.com/showthread.php?t=11381
    Although at 1500 bits/sec I'm surprised you are hitting the 2GB file threshold on very many of your conversions. There is yet another option assuming odml extended files fail on your player. Convert the DVD in two parts. Breaking it near the middle using the scissors feature.

    Definitely don't do more "quality" than actually translates into discernable viewing improvement for you. You are just wasting time (in the case of passes) and capacity in the case of your storage.

    ~KnoWei
     
    Last edited: Jan 9, 2008
  7. profcolli

    profcolli Well-Known Member

    Hey KnoWei, you beat me to the punch - I was researching my reply when you posted yours so I didn't see it!

    From the Archos site FAQ (for the 605, no info there on the 705):
    From an old (Nov 2006) thread:
    Although these comments are for the 605, it seems the 705 may have the same self-imposed limitation even with OpenDml support, but only testing with KnoWei's odml fix will tell.

    That is normal as different films are mastered differently. They may be either 30 (29.97) or 24 (23.976) fps - your original post made it seem as if you went from 29fps on the first pass to 23fps on the second pass of the same movie. I have seen that when transcoding from one format to another where the 3:2 pulldown is correctly detected (where the first pass is only an estimation). Again - don't worry about that.

    As KnoWei noted, higher bitrate and a second encoding pass (=much longer processing time) is hardly worth it on a hand-held device. Unless you plan on using the video-out from it to feed a much larger screen where you will see the difference.
     
  8. KnoWei

    KnoWei Well-Known Member

    Hi profcolli,

    I'm sure this just slipped by you :agree: but if this is what they are saying at Archos then it's misleading.

    If the device is using FAT32 as the file system then it should support max file sizes of 4GB. That is of course different than supporting AVI files of greater than 2GB.

    Just for clarity for those readers still digesting the vagaries of file size restrictions...

    The 4GB restriction on the device in question is (apparently) a function of the file system the mfg chose for storing data on the device. i.e. FAT32.

    The 2GB restriction on AVI files sizes is a function of the original spec for AVI.

    The 2GB restriction on AVI files can be overcome using a special AVI conversion option called OpenDML (odml). But your player may not support this modified AVI format. The 4GB restriction cannot easily be overcome since it is constrained by the way your device was programmed at the factory.

    ~KnoWei
     
  9. maclen

    maclen Member

    KnoWei and profcolli,

    Thanks for the great responses.

    I didn't mean to suggest that I can only get a bitrate of 1500 at the 2gig threshold. Actually, if I wanted to, for the average length movie, I could obtain a 2000 bitrate. The problem arises, as you have noted, when the movie is long (say 3 hours). Then, the bitrate is lower than 1500 for a 2gig file.

    Thanks for the explanation of the fps issue. I finally get it.

    KnoWei, you make an interesting suggestion about splitting files so as not to run afoul of the file size limitation. I actually tried that with my Archos device without success. However, I was attempting to copy .vob files, which my player reads and records. As an experiment, I tried to transfer three different DVD movies by using the .vob passthrough setting in cloneDVDmobile. Because each file was over 4gigs (the maximum file size for my player for all files, except avi files), I decided to make two files of each movie. (For example, if one movie had 26 chapters, I would use the scissors option and make one file for chapters 1-13, and the other file for chapters 14-26.) In each instance, the first file would not play (the same error message was shown on my device: "File is damaged or incomplete.") However, interestingly, each second file played perfectly. When I called the tech support at Archos, they said that they had received similar complaints about the cloneDVDmobile conversion program (and other programs) and indicated that in the splitting of files, somehow important information to play the files was omitted from the first file but not the second. I have no idea how to fix this. The only reason I bring it up is whether you would have the same problem with splitting an avi file larger than 2 gigs.

    Thanks again.
     
  10. profcolli

    profcolli Well-Known Member

    I understand that, but the Archos FAQ (and the forum thread in French) state that Archos deliberately set a 2GB file size limitation even though they support OpenDml - which was why I quoted it. Only testing will tell if it is true for the 705. 8)

    As for maclen's problems with split files, I would have thought that the second file would be the more likely candidate for corruption rather than the first [​IMG]
     
  11. KnoWei

    KnoWei Well-Known Member

    Odds are in your favor maclen that a movie split into two AVIs would not have this problem. That's because you are converting to an entirely different file structure than with the VOB approach. When the AVI is created the encoder is going to create the necessary header information to go with it.

    I agree with profcolli. I would have expected the first VOB file to work and the second to fail. That headscratcher is coming in handy already. :agree:

    BTW profcolli - I had four years of Latin 1 :D so I don't even try reading French. I'm restricted to menus at Italian resturants. I did think it was odd that Arcos would blame the 2GB restriction on FAT32.

    ~KnoWei
     
  12. maclen

    maclen Member

    Well, sorry to digress about the .vob experiment. KnoWei, that's exactly what the Archos tech said; that somehow the header must have been left off each of the first three .vob files. I guess I wanted to try copying .vob files (since my device recognizes them) and I was being lazy, since the .vob passthrough option for a 2 hour movie is about 10 minutes compared to the hour conversion to an avi file. But I'll stick with the proven method.

    Thank you both for your help.
     
  13. profcolli

    profcolli Well-Known Member

    Perhaps it is time for a system upgrade. I can do a 2 hour movie-to-avi in around 20 minutes with just an Intel E4300 Core2Duo (overclocked to 2.7GHz) and 2GB PC-5400 ram.

    KnoWei - I did Latin for four years too - Amo, amas, amat and all that. :D

    However, I also live in Montreal so even the Italian restaurant menus are in French. :doh: Roughly translated, the quote I posted was that "even though Archos supports OpenDml and uses a 4GB Fat32 system, they have fixed a file-size limitation of 2GB as a technical choice."