VOB Passthrough Quality?

Hi,

I was wondering if anyone out there has had issues with VOB Passthrough quality?

I recently ripped my Phoenix Nights Series 1 DVD using DVDFab to Mobile and selected to rip each episode as a single VOB file using the vob passthrough method. I was under the impression that the VOB passthrough method would basically stitch or extract the relevant VOB’s together WITHOUT ANY loss in quality, i.e 100% quality of the original in exactly the same format. Is this assumption incorrect?

The reason I ask this is because when I play the VOB file on my AppleTV at 1080p resolution the VOB file quality is noticably worse than playing the original DVD disc in my DVD Player which is upscaling the DVD to 1080i. There is noticable pixelation and a loss of sharpness on the VOB file… Did I do anything wrong in creating the VOB? Is this perhaps an issue with DVDFab?

Any help appreciated.
Kind Regards,
Paul.

It normally does what the name implies–passes the original MPEG-2 video to the output file at the original bitrate. Not sure what you are seeing there. How do the file sizes compare, original vs. processed VOB?

your dvd player upscaling probably only works on the original dvd format.

so the difference is likely due to comparing an upscaled picture with a non-upscaled one.

if you were to disable your dvd player upscaling then the vob passsthru should look just like the original dvd.

ps how big is the TV screen you are using ?

Good call, cyb.

Hi guys,

In terms of filesize/bitrate the single VOB and VOB’s are almost the same, but I am stripping out unwanted soundtracks, subtitles etc so there is likely to be some difference, but not enough that leaves me to believe there has been a loss in quality.

cby, I see your point… but perhaps you may be able to explain it a little more for me? I was under the impression that upscaling doesn’t affect the quality of the video, it just alters the sizing/ratio of image information such that it plays better at higher resolutions… One of the things that reinforced that for me was that there was noticable pixelation and areas where colour changes are noticable instead of smooth in the VOB so I couldn’t see how upscaling that in my DVD player and outputting at 1080i (instead of 1080p in the case of the VOB) could remove pretty much all of that and make the image look sharper. Pixelation in video is usually caused by compression no?

Kind Regards,
Paul.

The quality of the VOB Passthrough is EXACTLY the same as the DVD. It is a straight stream copy. The only change is the way the streams are combined into the new VOB file (i.e. removed some streams).

The better question is how are you getting the VOB content to your AppleTV? Last I heard, the AppleTV was not able to grab files directly from a file share. You first had to import them into iTunes or something. It is likely that the video is being changed to H264+AAC on either the import to iTunes or on-the-fly as the stream is sent to the AppleTV. This is likely where your pixalation is occuring.

Hi,

My Apple TV is running ATVFlash which opens it right up. It installs a whole bunch of stuff including nitoTV which allows you to define network shares. I have a 2TB NAS drive providing my content so there is no change in format, the VOB’s are being accessed through the network share and not through iTunes.

Tried to disable upscaling on my DVD Player but couldn’t see a way of doing it. There were 3 output resolutions for HDMI (576p, 720p and 1080i) and I changed the HDMI output to 576p and played the same episode and the quality was still better than the VOB. Going to try and get hold of a standard DVD player with no upscaling and plug that in to see the results…

If it is the upscaling that is the difference here, surely there must be some software out there which does exactly that which I could run my VOB’s through??

Anyway, there must be something amiss here which I have not understood as I agree regarding the comments about passthrough… as it was my initial understanding that the streams remained untouched and there was no loss in quality.

By the way, my TV is a Samsung 46’ 1080p LCD

Kind Regards,
Paul.

ATVFlash is interesting. In reading about it, it looks like you can alter the output resolution in NitoTV. You might try changing it to see what happens. Standard DVD output is 480i so anything greater than 480p will be changing the stream structure on-the-fly.

What is unknown is how NitoTV is using the hardware in the AppleTV. My understanding of the device is that it only supports decoding of H264. It would be a shame if NitoTV is converting the MPEG2 stream to H264 (creating the blockiness) in order to get it to play.