A question in relation to how far to render down

[akagi]

I have just started to use my Panasonic E55 to capture from the TV – recording in XP mode – and then trnasferring such to the PC. However the problem is a question of larger file sizes than I am used to. For example the WWII actioner ‘Raid On Rommel’ @1hr 34 Mins produced an MPEG2 file at 5.33Gb whilst ‘Starship Troopers’ @1hr 55Mins produced an MPEG2 at 7.17GB. Looking at the specs for this I see that they have a max VBR of 9578kbps. They obviously need rendering down to fit on a DVD-R but how far would people go before they forget the idea and just go with 2 discs.?

As an experiment I used Ulead VS 8 to render down Raid on Rommel to a max VBR of 6000Kbps producing a smaller file size of 4.07GB. For the life of me I cannot see any difference between the source and rendered video but is there(?) – obviously I cannot stare intently at the screen for 1hr 34 Mins x 2 without going blind (or nuts) .

Bitrate viewer was no help at all in the matter:

Original 5.33Gb file
Peak Bitrate 10196
Average Bitrate 7504
Peak Q Level 11.35
Average Q Level 5.68

Rendered 4.07Gb file
Peak Bitrate 6798
Average Bitrate 5658
Peak Q Level 7.00
Average Q Level 3.23

--As you can see this does not make much sense as looking at the Q level rendering down has supposedly IMPROVED the video quality!!!????

I just want an idea how far people would go with this rendering. As DVD-R media is VERY cheap now I would rather go with 2 discs than lose any appreciable quality but do not want to do this if it is not necessary.

I have done a lot of DVD-R burning so far but having to render has not been a major requirement to this point. I just want the benefit of other peoples experience (particularly bearing in mind a weird Panasonic codec) before I proceed.

[Soopafresh]

Perception is everything. If you can't see the difference, then there IS no difference, at the end of the day. Maybe even into the evening

If I understand your question correctly, you want to put around 3.5 hrs onto a single DVD but you're wondering if the quality will suffer too much.

If your source contains quite a bit of action, then it might be hard to hide the artifacts of a highly compressed target. Then again, it depends on what you're willing to tolerate when you see the final product. One man's Velvet Elvis is another man's Picasso.

[akagi]

Soopafresh or anybody, To clarify I am definately NOT looking at putting 3.5 hours onto 1 DVD but say 1Hr 45 Mins say.

Maybe its a question of my understanding how MPEG's actually work. Am I right in assuning that MPEG's and the bitrate associated with same is a function of what changes frame to frame such that a bitrate of 8000kbps means that in one second the MPEG has 8000 kb to carry all the changes in the video over that second. Have I understood this correctly?.

If the above is the case then am I right in assuming that a render down will not effect EVERY frame in the video but ONLY those frames where the action/frame to frame changes have exceeeded the bitrate allowance - at which point artifacts will appear?

If that is the case those 2 men sitting at a table (for example) in my Raid on Rommel video are probably of EXACTLY the same clarity whether it be at 9578kbps or 6350 kbps but the point where things would show is in the action sequences.

Have I understood this correctly - rendering down is 'trimming the fat' from the file size but you have to know when to stop as the bitrate 'allowance' goes below the required bitrate for ONE OF the scenes?

If this is the case it comes back round to calling on peoples' experience. For the amount of burning I have to do I cannot check every scene but I do not want to lose ANY quality if possible but only want to go to 2 discs or dual layer IF I HAVE TO. What bitrate would they believe is a fair minimum for the average actioner - at what rate in their (far greater) experience would their alarm bells start ringing? I want people's idea of a threshold point.

I hope I am explaining myself properly and that I have understood the MPEG element.