VideoHelp Forum
+ Reply to Thread
Results 1 to 30 of 30
Thread
  1. First time on this website that I asked a question and couldn't get a clear answer, so I re-formatted my question. Can someone please tell me what software I can use to compress 4GB mpeg2 (2 hours video) to 1GB mpeg2? I want to compress slowly to have OK quality.
    My previous question was how to convert 4 dvds(16GB, 8 hours) into 1 dvd (4GB) and I got many non-answers, including the quality would be too poor (fact: I have 8 hours of vcd video on a DVD and I think the quality is good), buy a laptop and put the videos on there. Another answer was convert to xvid/dvix, but I decided against that because xvid/divx is not playable on older DVD players. On the other hand, I found that mpeg2 plays on all DVD players that I have tested. Another answer was to use DVD Shrink with DVD Rebuilder, but I did not understand clearly the steps involved to do that. I don't think that DVD Rebuilder can take a 16GB DVD and compress it to 4 GB.
    Anyway, a clear answer to this question would allow me to get to work and complete this job for somebody who is waiting for the one disk that has the 7.5 hours of video. The quality doesn't have to be that great. The 7.5 hours of video is a speech contest, so there is little motion. Clear enough audio is probably more important that clear video.
    Quote Quote  
  2. Roadrunner JohnnyBob's Avatar
    Join Date: Feb 2007
    Location: United States
    Search Comp PM
    You could use a standalone DVD recorder that has an 8 hour setting.
    Quote Quote  
  3. Member
    Join Date: Oct 2004
    Location: Freedonia
    Search Comp PM
    You got answers - a LOT of them. I responded and told you to use DVDShrink. NOBODY told you that what you proposed would work. Bluntly put, it's not MY fault that you aren't smart enough to recognize good advice when you get it.

    Use DVDShrink to do this - assuming you're smart to understand that this IS an exact answer to your question.
    Quote Quote  
  4. jim, I must say they way you phrased this "question"/complaint begged for answers like Johnny gave above.

    "Another answer was to use DVD Shrink with DVD Rebuilder, but I did not understand clearly the steps involved to do that." ........OK......what do you WANT?!?!?!? for them to come do it for you? There are countless "how-tos" on DVD Shrink on this site! It's not that hard, really.
    Quote Quote  
  5. Are you saying that DVD Shrink can do the entire job (combine 4 DVDs (2 hours each) into one large 16GB DVD and then shrink down to one 4GB DVD? The problem is, in my last posting, looking at the answers, I was confused about whether I need to use DVD Shrink and DVD Rebuilder, or can I just get by with using DVD Shrink?
    Quote Quote  
  6. Member
    Join Date: Jul 2002
    Location: United States
    Search Comp PM
    You can try TMPEG and set your output as low resolution 352x240. I think you can put 6 - 8 hours of video on a single DVD with acceptable quality. The quality is as good as VCD. If you try it and let us know how it works out for you.

    vcdlover
    Quote Quote  
  7. When you say TMPEG, what is the full name of that software? If I use that software, is the output still in mpeg2? When you say "low resolution 352x240", does that correspond to a certain bit rate?
    Quote Quote  
  8. Member
    Join Date: Jul 2002
    Location: United States
    Search Comp PM
    Originally Posted by jimdagys
    When you say TMPEG, what is the full name of that software? If I use that software, is the output still in mpeg2? When you say "low resolution 352x240", does that correspond to a certain bit rate?
    You can find more info from here http://www.videohelp.com/tools/TMPGEnc_Plus. There are three outputs for MPEG2 templates and one of them is low res. Basically, it's an MPEG1 video with MPEG2 audio spec and most if not all DVD author software will accept the output MPEG2 file. Have fun...
    Quote Quote  
  9. Thanks for the info on TMPGEnc_Plus. I am looking at the various answers given. One question I have is about DVD Shrink. The software (it seems) only allows me to shrink a DVD by 50%. But, to fit 16GB on a 4GB disk, I need to shrink by 75%. Is it possible to use DVD Shrink and shrink by 75%? If not, it seems that I won't be able to use DVD Shrink in this particular case.
    Quote Quote  
  10. Member
    Join Date: Jul 2002
    Location: United States
    Search Comp PM
    Originally Posted by jimdagys
    Thanks for the info on TMPGEnc_Plus. I am looking at the various answers given. One question I have is about DVD Shrink. The software (it seems) only allows me to shrink a DVD by 50%. But, to fit 16GB on a 4GB disk, I need to shrink by 75%. Is it possible to use DVD Shrink and shrink by 75%? If not, it seems that I won't be able to use DVD Shrink in this particular case.
    I've used Shrink a few times, but didn't quite like it. So, I can't say if it's OK to reduce to 75%. If I want to backup my movies, I always use DVD2ONE. You can compare Shrink, DVD2ONE and DVDFAB together because these three apps can shrink or transcode to the size you want.
    Quote Quote  
  11. Mod Neophyte Super Moderator redwudz's Avatar
    Join Date: Sep 2002
    Location: USA
    Search Comp PM
    A few simple answers. Yes, you can use Shrink, by running the video through twice, and selecting a custom output size of 1GB.

    Or to compress 2 hours (4GB) of MPEG-2 to 1GB with a MPEG encoder, you will need a bitrate of about 880Kbps:



    VCD is 1150Kbps and is MPEG-1, so it will be worse than VCD quality. You can reduce the MPEG-2 framesize to 352 x 240 pixels (NTSC) and reduce the audio quality down and get a bit more quality. Most MPEG-2 encoders can do this. I would use a two pass encode with variable bit rate. Try this with a short MPEG-2 clip and see how it looks.
    Quote Quote  
  12. Roadrunner JohnnyBob's Avatar
    Join Date: Feb 2007
    Location: United States
    Search Comp PM
    Originally Posted by jimdagys
    Is it possible to use DVD Shrink and shrink by 75%?
    Try it, then you'll know for sure. You can drag as many titles as you want from your hard drive into DVD Shrink reauthor mode. I suspect that DVD Shrink will inform you that it's not possible to shrink that much data to fit on a single-layer DVD. However I've seen shrinkage below 50% available in many cases, so I can't say for sure. Maybe it has a chance if shrinking to fit on a double layer 8.5G DVD.
    Quote Quote  
  13. jimdagys
    you can use Shrink on already shrunk vobs as many times as you want (2x, 3x, etc). Quality decreases each time though.
    Quote Quote  
  14. Simple question: how to compress 4GB mpeg2 to 1GB mpeg2
    It' simple:

    File size = running time * bitrate

    So reencode with 1/4 the bitrate.

    As others have pointed out, the video will probably look like crap. You can make it look a little better by using half D1 or quarter D1 resoution. But you'll be trading off resolution for fewer macroblocks.
    Quote Quote  
  15. Member
    Join Date: Sep 2007
    Location: Canada
    Search Comp PM
    Convertxtodvd should do this (the 8hour => 1dvd) easily in almost 1 step, and author it to DVD format such that it will play in standalone players

    As you already know (and others have pointed out) quality will suffer, but will depend greatly on the quality of your source.

    I suggest you compile the project and encode a few minutes, then abort encoding to test the output to see if the quality is acceptable first (just run the encoded .vob file through your software media player)

    This should work, I just tried a mini-test of 8 hours of video.

    Good luck
    Quote Quote  
  16. Banned
    Join Date: Nov 2005
    Location: United States
    Search Comp PM
    Originally Posted by jimdagys
    First time on this website that I asked a question and couldn't get a clear answer, so I re-formatted my question. Can someone please tell me what software I can use to compress 4GB mpeg2 (2 hours video) to 1GB mpeg2? I want to compress slowly to have OK quality.
    My previous question was how to convert 4 dvds(16GB, 8 hours) into 1 dvd (4GB) and I got many non-answers, including the quality would be too poor (fact: I have 8 hours of vcd video on a DVD and I think the quality is good), buy a laptop and put the videos on there. Another answer was convert to xvid/dvix, but I decided against that because xvid/divx is not playable on older DVD players. On the other hand, I found that mpeg2 plays on all DVD players that I have tested. Another answer was to use DVD Shrink with DVD Rebuilder, but I did not understand clearly the steps involved to do that. I don't think that DVD Rebuilder can take a 16GB DVD and compress it to 4 GB.
    Anyway, a clear answer to this question would allow me to get to work and complete this job for somebody who is waiting for the one disk that has the 7.5 hours of video. The quality doesn't have to be that great. The 7.5 hours of video is a speech contest, so there is little motion. Clear enough audio is probably more important that clear video.
    in a nutshell you need to re encode the mpeg2 using 1/4 the bit rate of the original mpeg2. as for what software, any mpeg encoder that accepts mpeg2 as input and can produce mpeg2 as output will do, memcoder, ffmpeg, tmpg, procoder, cce, the list is almost endless.
    Quote Quote  
  17. Thank you for all the replies. I see light at the end of the tunnel. I used DVD Shrink on each of the 4GB dvds and shrunk them down to 2GB each. Now I have 4 dvds on my hard drive, each 2GB each for a total of 8GB. Video quality still looks good and I still retained the chapter points on each dvd. At this point I am thinking of several options:
    1) Run each (all 4) of the 2GB dvds through DVD Shrink again, and shrink again by 50% so that I will have 4 (1GB each) dvds. Then use DVD Shrink again (no shrinking) to combine each of the 4 dvds into one final 4GB dvd, (with 4 titles) which should be the finished product.
    2) Use DVD Shrink again (no shrinking) to combine each (all 4) dvds into one (8GB) dvd (with 4 titles) and then use DVD Shrink again to shrink the (8GB dvd) into one final 4GB dvd which should be the finished product.
    My question is, which of the above options is best?
    Last question, if I start again with the original mpeg2 files (four 4GB mpeg2 files), and used one of the suggested mpeg2 encoders (memcoder, ffmpeg, tmpg, procoder, cce, thanks again for suggesting these) to reduce each mpeg2 file to 1GB and then author into DVD, would this method give a better result than the above two (DVD Shrink) options? My understanding is that DVD Shrink reduces file size in a different way (better, worse?) than using mpeg2 encoders to reduce file size.
    Quote Quote  
  18. I have a a question for redwudz. I am doing a side experiment to see if I can just lower the bit rate of the original 4GB mpeg2. I am trying to use TMPGEnc. On page 1 of the wizard I choose vcd-pal but on page 4 of the wizard (see screenshot 1), the bit rate is fixed (greyed out) at 1150kbps so I cannot reduce it. How can I reduce the bit rate below 1150? If I go back page to page one of the wizard, and choose DVD pal-low res, then on page 4 of the wizard (see screenshot 2) I can't reduce the bit rate below 750, which corresponds to a estimated file size of 1798MB which is way too big.



    Quote Quote  
  19. It looks like you picked the standard PAL VCD project. VCD has a fixed bitrate. If you want VBR, before encoding go to the MPEG Settings dialog, the System tab, and select MPEG 1 VCD non-standard.



    Then go back to the Video tab, unlock the "rate control mode" setting (right click on the text lable and select unlock), select 2-pass VBR and the bitrate parameters you want.
    Quote Quote  
  20. Mod Neophyte Super Moderator redwudz's Avatar
    Join Date: Sep 2002
    Location: USA
    Search Comp PM
    You can unlock most of the controls on TMPGEnc if you R click on the function, such as 'Bitrate'. Then you should see a 'Unlock - Lock' menu. Or you can unlock them all by using a template.

    I think jagabo answered most of your question. But with TMPGEnc, when you go 'outside the norm', you don't want to use the Wizard most times. These notes are for TMPGEnc 2.5 Plus. Other versions of TMPGEnc encoder may be different.

    Kill the Wizard if it starts. Most all of the settings in TMPGEnc are adjustable. You specified MPEG-2 originally, and that's the settings I was showing. MPEG-1 is probably a better choice with a low bitrate file. And TMPGEnc encoder is free for MPEG-1. (At least it was, haven't checked lately.)

    The main TMPGEnc page should be open. In 'Setting' open the MPEG setting page, and select 'MPEG-1 Video'. I would select '2 pass VBR(VBR)', then L click 'Setting' to the right. For a Average bitrate setting, try 850kbps.

    TMPGEnc normally uses MPEG-1 Audio level 2, which is probably OK as is for you. One change you want to make in the 'Audio' tab is to set the sampling rate to 48K, instead of the standard VCD 44.1K as that's not DVD compatible.

    TMPGEnc may set the audio back to 44.1K, make sure it's 48K before you encode. Also check to see the framesize is correct. For me in NTSC land, I use 352 X 240, MPEG-1. Run the encoder for 5 minutes or so and see what the output is. Gspot should be able to tell you the bitrate and other info of the encoded file.

    TMPEGnc may do 'Analyzing' for some time before the encode starts with 2 pass VBR. Wait for that to finish before stopping to see how it looks.

    Sorry, it's been a while since I used the program. But there should be plenty of guides for it on it's toolpage.
    Quote Quote  
  21. Thanks for the detailed info on TMPGEnc (see screenshot). I used a bit rate of 1000kbps because the video is 110 minutes. I am in pal country and the default size shown is 720x576. Question: Should I leave that number as is or should I change it to something else? How does one know what size should be used?
    One last question, how does using TMPGEnc (to reduce file size by 75%) compare to using DVD Shrink (to reduce file size by 75%) in terms of the video quality of the final product? In other words, which method (TMPGEnc or DVD Shrink) will give a clearer picture under these circumstances of file reduction? This is the question I am really trying to find out.

    Quote Quote  
  22. Member mats.hogberg's Avatar
    Join Date: Jul 2002
    Location: Sweden (PAL)
    Search Comp PM
    At that bitrate, no more than std VCD resolution; 352x288

    /Mats
    Quote Quote  
  23. Originally Posted by jimdagys
    I used a bit rate of 1000kbps because the video is 110 minutes. I am in pal country and the default size shown is 720x576. Question: Should I leave that number as is or should I change it to something else? How does one know what size should be used?
    There's not absolute way of knowing what frame size to use for any particular video. A 2 hour still frame of a bowl of fruit will encode at 720x576, 1000 kbps and look great. A movie shot with a camcorder from a kayak shooting down the rapids on a bright sunny day will be unwatchable. But as a very general rule: for 4000 kbps or more use full D1 (720x574 PAL, 720x480 NTSC). For 2000 to 4000 kbps use half D1 (352x576, 352x480). For 2000 kbps or less use quarter D1 (352x288, 352x240).

    What you are doing is trading off resolution (overall sharpness) to get fewer macroblock artifacts (blockiness). In the case of quarter D1 you will also be trading of temporal resolution if your source is interlaced (the video will be a little more jerky when watched on TV).

    2x enlarged crops
    720x480 8000 kbps
    720x480 1000 kbps
    352x480 1000 kbps
    352x240 1000 kbps


    The smaller frames were resized back to the original's full screen size approximately like DVD player would (I used VirtualDub's bicubic filter). Then all frames were enlarged 2x with a nearest neighbor filter to make the defects more obvious. Note how the 720x480 1000 kbps frame has some sharp edges left but has very heavy macroblocking. The 352x480 image has a less sharp picture but still has some obvious macroblocking. The 323x240 frame is the least sharp picture but little macroblocking.

    These are crops from a single frame of a single video. Use them only as a general guide of the effect of frame size on low bitrates, not the absolute last word on what frame size you should use in your videos.

    Originally Posted by jimdagys
    One last question, how does using TMPGEnc (to reduce file size by 75%) compare to using DVD Shrink (to reduce file size by 75%) in terms of the video quality of the final product?
    I haven't use DVDShrink very much but from what I understand, if you're going to shrink a movie a lot, reencoding will give much better results.
    Quote Quote  
  24. Member mats.hogberg's Avatar
    Join Date: Jul 2002
    Location: Sweden (PAL)
    Search Comp PM
    Originally Posted by jagabo
    I haven't use DVDShrink very much but from what I understand, if you're going to shrink a movie a lot, reencoding will give much better results.
    Quite true. The DVDShrink way is much faster than reencoding, and good for (this is just my opinion) up to 75%. More than that, reencoding really makes a difference. While reencoding, you may also change resolution - shrinking always keeps the resolution of the original, not good if you need to shrink much (like in your case; down to 25%!).

    /Mats
    Quote Quote  
  25. I sliced out a 1 minute clip of the video that I am trying to compress file size by 75% (a necessary requirement) and tried 3 different settings with TMPGEnc. Using 1000kbps as a constant (all 3 methods yielded the same file size), I tried 3 different settings on the video size:
    1) 352x288
    2) 352x576
    3) 720x576

    Screenshots are directly from Media Player Classic

    1)Screenshot 1 shows 352x288
    The video has sort of a vcd type blurry softness (when blown up to be the same size as screenshot 2).

    2) 352x576 gave a video that was terribly squished in one direction, totally unacceptable

    3) Screenshot 2 shows 720x576
    The video of 720x576 has sort of a sharp blockiness. However, the screenshot doesn't really show the shortcomings of this video setting (that can be seen when playing the video).

    I would have to say that 352x288 is the best.
    My question is: Is there any other settings for video size that I should try? I read a bit about these settings (video size) and am totally confused, so the best thing is just try different numbers and see what is the result.




    Quote Quote  
  26. Mod Neophyte Super Moderator redwudz's Avatar
    Join Date: Sep 2002
    Location: USA
    Search Comp PM
    I think you have about got it figured out. 1) 352x288 is likely the best choice. The file size will be the same on all three clips as the bitrate is the same. Bitrate and playing time vs desired file size are the keys. Since you are making a DVD, you need to stay with the compliant DVD sizes. As in 'WHAT IS' DVD to the upper left.

    With a smaller framesize, the lower bitrate will yield less artifacts or blocking. The only possible improvement I can think of would be some light filtering. But that will greatly increase the encoding time and I wouldn't recommend it. The total encode time will be long enough as is.

    I'd go with those settings and let the encoder run. I would also err on the smaller side with your encoding settings. You don't want it to come out larger than will fit on your media and have to re-encode or Shrink. Leave about 100 - 200MBs smaller than 4.37GB, or about 4.2GB for a DVD-5 disc to allow for the authoring and size errors.
    Quote Quote  
  27. There is something strange going on with my version of TMPGEnc. When I use the setting
    "MPEG-1 Video -CD (Non Standard)" , see screenshot, as suggested above by Jagabo, then when I change the bit rate kbps from 900 to 1100, there is absolutely NO change in output file size. I am certain I am getting the bit rate changed properly, and Gspot for the result is showing the bitrate that I select, ie 900 or 1100kbps, but the converted file size is exactly the same. However, if I choose "MPEG-1 System (VBR)", see screenshot, then when I change the bit rate from 900 to 1100, then the file size does change. Can someone explain why in the first case (when changing bit rate) there is no change in file size, but in the second case (when changing bit rate) the file size does change. Of course I would expect the file size to change when I alter the bit rate from 900 to 1100 kbps. I want to be able to fine tune the bit rate for a desired file size. Maybe it is necessary to choose "MPEG-1 System (VBR)" instead of "MPEG-1 Video -CD (Non Standard)". In both cases I am choosing "2-pass VBR" under Video Mpeg Setting.
    One other question, should I use (tick) the "noise reduction" box? Will that give a better picture? If I do that, it will take about 110 hours to process 7.5 hours of video.

    Quote Quote  
  28. Originally Posted by jimdagys
    2) 352x576 gave a video that was terribly squished in one direction, totally unacceptable
    Whatever you were using to view the MPG file wasn't correcting for the DAR. When you watch this on TV via DVD player the image will automatically be stretched horizontally to the final 4:3 DAR. So this is not a reason to reject the 352x576 frame size.

    Originally Posted by jimdagys
    There is something strange going on with my version of TMPGEnc. When I use the setting
    "MPEG-1 Video -CD (Non Standard)" , see screenshot, as suggested above by Jagabo, then when I change the bit rate kbps from 900 to 1100, there is absolutely NO change in output file size. I am certain I am getting the bit rate changed properly, and Gspot for the result is showing the bitrate that I select, ie 900 or 1100kbps, but the converted file size is exactly the same.
    Are you sure you were using the non-standard option? The behaviour you describe is what you get with the standard option.

    The VCD spec calls for a fixed bitrate of 1150 kbps in the video stream. The spec allows for lower video bitrates but calls for the file to be padded so that the file size remains the same. In other words, if you encode at 500 kbps another 650 kbps of junk is added to maintain the fixed file size. So no matter what bitrate you choose the final file size is the same.

    When you use the standard template in TMPGEnc you get the padding and a fixed file size. When you use the non-standard template you don't get the padding and the file size varies with the bitrate.

    I know you said you're sure you set the bitrate correctly but just to be certain:

    The average bitrate determines the file size. The Min and Max settings determine how much less and more bitrate can be allocated to frames that don't and do need it. But the differences will average out to the average bitrate setting.

    Another possible issue: you are dealing with very low video bitrates. The audio is becoming a significan't portion of the total bitrate. Changing the video bitrate by 10 percent will change the file size by less than 10 percent because of the audio.

    You might also consider using a lower audio bitrate so you can use a little more on the video.

    Originally Posted by jimdagys
    However, if I choose "MPEG-1 System (VBR)", see screenshot, then when I change the bit rate from 900 to 1100, then the file size does change.
    I'm not sure what other restrictions are lifted when you use MPEG-1 System (VBR) instead of VCD non-standard. You will probably be OK with either since you will likely be playing on a DVD player, not a first generation VCD player. You should note that the ability to play VCD is not required in the DVD spec but the ability to play MPEG 1 video streams is. And the ability to play MPEG audio streams is not required on NTSC players (most support it though), but is required on PAL players.

    Originally Posted by jimdagys
    should I use (tick) the "noise reduction" box? Will that give a better picture? If I do that, it will take about 110 hours to process 7.5 hours of video.
    Noise is a killer for MPEG compression. MPEG compression is based largely on two properties of video: 1) Each 8x8 pixel block (64 pixels) typically contains less than 64 different colors. So it's possible to describe the 64 pixels with far less information than would be required by 64 different colors. 2) Many parts of the frame do not change from frame to frame -- all the unchanging parts do not have to be included in every frame. Excessive noise makes both of these untrue.

    So noise reduction can lead to better encoding. But you have to be careful. Noise reduction isn't perfect. It doesn't eliminate just noise, it also eliminates some small details. And it can lead to other artifacts. To reduce the noise enough to make a big difference in the bitrate requirement often damages the video too much. But given you are working with very low bitrates you may find some noise reduction acceptable. You'll have determine this experimentally.
    Quote Quote  
  29. Thanks for the detailed info. Regarding your question, "Are you sure you were using the non-standard option?"
    Yes I am sure that I choose that option. Maybe my version of TMPGEnc is a little weird. So I will just use the option,
    "MPEG-1 System (VBR)", and do the converting. After I get all 4 files shrunk into 1gb files, then I will try to author (and insert chapter points) into DVD. I'll report back, hopefully with good news.
    Quote Quote  
  30. I am going to start a new thread (how to author a DVD from mpeg1 files) because my problems are now different than when I started. I was successful to create (compress 4GB mpeg2 to 1GB mpeg1) using the software TMPGEnc. I found that using TMPGEnc for this amount of compression (75%) is far superior (better picture) than using DVD Shrink.
    Quote Quote  



Similar Threads