How small will converted MPEG2 to MPEG4 be?

[cathersal]

I am ordering a new system that I will use with SageTV 6.4. I want to record in Clear Qam digital MPEG2 and then automatically convert it into MPEG4 so that I can copy it to myself over the internet. For this reason, i need the files to be as small as possible.

Currently, I am using software MPEG1 encoding of analog signals and and get about 600 megs per hour of SD. Does anyone have an idea what I could expect when I convert from MPEG2 to MPEG4? I know that it will depend on the bit rate I am getting on the digital signal, but I'm just trying to get a ballpark range so I can see if my idea will work.

When I see TV shows on the internet in MPEG4 I see 30 minute shows in as little at 170 megs, so I'm wondering if I could expect the same.

Thanks!!

[stanger89]

Probably 4GB/hr or so, if I had to guess. Depends on what quality you're happy with. You won't get it below 1GB/hr unless you don't care if it remains HD.

[dvd_maniac]

This really depends on what version of Mpeg-4 you want to encode into.
Mpeg-4 ASP or AVC...
ASP will require more space but is fast to encode, while AVC requires about half the space at the same quality but takes longer to encode.

I myself cut out commercials and encode my HD to 720p at around 300MB per 43 minute episode (I don't keep 5.1 audio though)...

[CollinR]

Originally Posted by stanger89

Probably 4GB/hr or so, if I had to guess. Depends on what quality you're happy with. You won't get it below 1GB/hr unless you don't care if it remains HD.

Not a bad guess, by using Sage's internal compression set for high quality I get ~3.6GB per hour.

[stanger89]

Well, I've done a couple 1080i movies -> 720p H.264 and they come out to be 6-8GB or so

[cathersal]

dvd_maniac,

What you are doing sounds Perfect. I also don't care about 5.1 sound and as I am using MPEG1 now, just about anything will look better!

How are you getting your files so small. Are you using some of the custom add-ins, or just the out of the box Sage converter?

Thanks!

[dvd_maniac]

Originally Posted by stanger89

Well, I've done a couple 1080i movies -> 720p H.264 and they come out to be 6-8GB or so

I should start out by stating that I do not use Sage's internal compression methods, So I do not know how big they end up.
Also, you could do a 1080i -> 720p encode and end up with a 500MB file or a 20GB file. It depends on the bitrate used. Given a movie that has very little motion or scene changes the 500MB and 20GB files might look almost identical.
I ripped Transformers Blu-ray movie and encoded it using various bitrates and played them for friends and family on my 57" 1080p LCD and asked them to QC them for any visible quality loss(Blu-ray rip, 8GB, 5.4GB, 3.2GB, 2.4GB and 1.2GB). They could not tell the difference until I got to the 1.2GB filesize and even then only slight difference.

IMHO a 5-6GB or a 1-2GB 720p (around 90minute) movie would be almost indistinguishable from one another if properly encoded. Unless the movie had very fast moving action scenes.
Just a lot of wasted bitrate.
Again...IMHO

[dvd_maniac]

dvd_maniac,

What you are doing sounds Perfect. I also don't care about 5.1 sound and as I am using MPEG1 now, just about anything will look better!

How are you getting your files so small. Are you using some of the custom add-ins, or just the out of the box Sage converter?

I use a program called Staxrip with X.264 and HE-AAC audio codecs.

I used to have it setup with Dirmon to automatically scan for cuts using VideoReDo, then I'd manually check the cuts every few days and batch them up into another folder where Dirmon would again take over and encode them using a custom Staxrip profile.
You could then use a program called Fling to automatically upload them to an FTP site if that fits your needs.

[stanger89]

Originally Posted by dvd_maniac

I should start out by stating that I do not use Sage's internal compression methods, So I do not know how big they end up.
Also, you could do a 1080i -> 720p encode and end up with a 500MB file or a 20GB file. It depends on the bitrate used.

Neither do I, x264, with YADIF deinterlacing and spline resize. It's about a 30 hour process on a 2.2GHz Core2 Duo. I tried a few CQ settings and anything less than 22 produced significant artifacting, even on my laptop monitor.

Those settings result in about 6-8GB encodings for a 1.5-2hr vid.

[dvd_maniac]

30 hours? Wow...

When I started out with encoding my DVD collection I was using 4x250GB drives in a raid-5 array and had right around 700 DVDs. So I knew that quality would have to suffer somewhere. Maybe I have become accustommed to a lower quality. But since HDDs have come way down $$$ and up in capacity along with converting all my tuners to HD I've upped the quality a little. I currently use 24 to convert DVDs with no risizing and they usually come out to about 300-400MB. Recorded TV movies, both 1080i or 720p, gets encoded to 720p with QC at 26.
My Q6600 4*2.4Ghz crunches them out pretty fast. But I do notice the lower the QC # the longer it takes. I will try Transformers again at 720p & QC = 22 and time it to see and also look at the PQ again since I got a few new HDTVs since then.

[stanger89]

Originally Posted by dvd_maniac

30 hours? Wow...

Forgot I wasn't doing two-pass (since it's CQ it's only 1), so it's more like 13-15 hours.

When I started out with encoding my DVD collection I was using 4x250GB drives in a raid-5 array and had right around 700 DVDs. So I knew that quality would have to suffer somewhere. Maybe I have become accustommed to a lower quality.

That's probably got something to do with it. Quality seems to be something you sort of "get used to". I used to scoff at those who said they couldn't watch SD anymore, or that SD was "crap". I used to be one of the ones who said HD wasn't that much better.

But since switching probably 90% of my movie viewing to Blu-ray and probably 90$ of my TV watching to HD (combo of HD PVR+HDHR), I can now sympathize with them. SD is harder to watch now (still watchable though).

It's sad to say (sorta) but after living almost completely in HD, it's to the point where HD looks normal now, not special.

But since HDDs have come way down $$$ and up in capacity along with converting all my tuners to HD I've upped the quality a little. I currently use 24 to convert DVDs with no risizing and they usually come out to about 300-400MB. Recorded TV movies, both 1080i or 720p, gets encoded to 720p with QC at 26.

Think I tried that once, I want to say the default in Ripbot264 is 24. I wasn't entirely happy with the quality there, far too much macroblocking. I remember trying 18, but that was huge might have been bigger than the MPEG-2 original.

My Q6600 4*2.4Ghz crunches them out pretty fast. But I do notice the lower the QC # the longer it takes. I will try Transformers again at 720p & QC = 22 and time it to see and also look at the PQ again since I got a few new HDTVs since then.

That would be about twice as fast as mine then, but if you're doing a 24p BD, mine will still be longer since it was 1080i60 video, that I deinterlaced to 720p60 (which would also increase the resulting size).

The only other thing I'll add is viewing ratio is really important to perception of quality. I normally view on a 110" wide, 1080p scope projection setup, from about 11 feet or so. Any flaw is pretty obvious with that, DVDs are noticably inferior to HD/Blu-ray on that setup, and the blocking from Dish/OTA HD compression is apparent. A friend got a new 32" Samsung A550 LCD and brought it over for a quick calibration the other night. We set it on top of my equipment rack right in front of my screen, so same seating distance, but about 1/10th the size. With that display it was pretty hard to tell the difference between DVD and HD, and HD looked pretty much artifact free.

[dvd_maniac]

Well then, my conclusion to this is to not spoil myself too much.
Although you bring up a great point as I just got done finishing my basement and I created a room 24x30 specifically to create a sports viewing mecca. Being in the Boston area kind of made it worth it. (Go Celtics, Bruins and BoSox and "Hopefully Pats" too).
I will be looking into a decent projector and do not want my current movies to look really bad...
How does an un-encoded DVD look on your setup?
Also, do you have a PC or Extender hooked up to your projector?

[stanger89]

Originally Posted by dvd_maniac

How does an un-encoded DVD look on your setup?

I guess "soft" would be the best way to describe them. I thought they looked really good until I started watching Blu-ray's. Guess my standards have increased.

Also, do you have a PC or Extender hooked up to your projector?

Both actually. Though since I got the HD100 I never used the PC for TV. In fact, it was basically decommissioned until I resurrected it as my Blu-ray player.

[dvd_maniac]

Thanx for the thoughts and helping me re-evaluate my storage policies. Although I'll still probably keep wife's boring dramas and kids stuff on the small end, I'll start thinking ahead and add a little more quality to some of the new stuff with action and high visually appeling movies.