Re-encoding at higher bitrates (Not for DVD burning)

[unclescoob]

How's everyone doing?

Suppose you do all your MPEG-2 cleanup and send it to HcEnc for re-encoding.

Let's assume that the original file size was 5,000-7000kbps VBR.

Now, suppose you push it up to super high bitrates (say 10,000kbps-15,000kbps 2-pass).

All other settings would be pushed to the best possible options available.

Would quality loss necessarily incur, or is it at least safe to say that, considering the alloted bitrates, quality loss did not necessarily take place?

[manono]

Would quality loss necessarily incur, or is it at least safe to say that, considering the alloted bitrates, quality loss did not necessarily take place?

Of course there's quality loss. You may not notice it, but since MPEG-2 is a lossy codec it's there. It doesn't matter what bitrate you use.

All other settings would be pushed to the best possible options available.

Do you know what those might be?

[jman98]

As manono points out but might not get the attention it deserves, you MAY NOT NOTICE IT, but yes, quality loss will occur. I'd bet that at bit rates like you propose, you won't notice it.

Do note that some of our experienced members are super critical when it comes to quality, so rather than just have them post and tell you that with their overblown warnings that your re-encoding will completely destroy the quality and it will be unwatchable, yada yada yada, why don't you just try what you propose and see if it meets YOUR needs rather than asking a bunch of (potentially) over critical strangers here about it.

[manono]

Do note that some of our experienced members are super critical when it comes to quality, so rather than just have them post and tell you that with their overblown warnings that your re-encoding will completely destroy the quality and it will be unwatchable, yada yada yada...

Hehe, I reencode DVDs all the time, filtering to improve the quality (I hope). But if you want lossless then you use a lossless codec, not MPEG-2.

[Cornucopia]

What I'm curious about is all this "MPEG2 cleanup" that seems to be necessary for some people. By and large, with VERY FEW exceptions, my Hollywood titles seem to have been very well encoded in the first place, so why mess up a good thing, eh? "If it ain't broken..."

Scott

[manono]

What I'm curious about is all this "MPEG2 cleanup" that seems to be necessary for some people.

I can only speak for myself, but I'm not the least bit interested in Hollywood's latest and greatest. And, as you say, they generally need no 'cleanup' at all.

[jman98]

Do note that some of our experienced members are super critical when it comes to quality, so rather than just have them post and tell you that with their overblown warnings that your re-encoding will completely destroy the quality and it will be unwatchable, yada yada yada...

Hehe, I reencode DVDs all the time, filtering to improve the quality (I hope). But if you want lossless then you use a lossless codec, not MPEG-2.

I was actually thinking of 2 other members who have yet (so far) to participate in this thread and I felt like heading their arguments off at the pass.

[jagabo]

Suppose you do all your MPEG-2 cleanup and send it to HcEnc for re-encoding.

Let's assume that the original file size was 5,000-7000kbps VBR.

Now, suppose you push it up to super high bitrates (say 10,000kbps-15,000kbps 2-pass).

All other settings would be pushed to the best possible options available.

Would quality loss necessarily incur?

Yes, of course. Any time you compress with a lossy codec you get losses. The question is how much loss you get. With 10 to 15 Mb/s your losses (relative to the cleaned video) will usually be minimal. If the cleaning you did was significant the final video may look better than the one you started with.

[2Bdecided]

Even at high bitrates, if you A/B compare still frames of original-vs-encoded, the visible differences can be large for some content. You just can't spot those differences in motion though. It's only relevant if you ever intend to process the video again from that re-encode, or grab stills.

noise-free smooth progressive content is far easier to encode than noisy or detailed and/or interlaced content. The former can be visually transparent at 5Mbps. The latter might not be at 15Mbps. Movies that people have "restored" are usually closer to the former.

Cheers,
David.

[unclescoob]

I have done a series of experiments, and have seen that the re-encoded product looks fantastic. So my question is answered and it does make sense: Although it may not necessarily be noticeable, loss does take place. I have also transcoded from MPEG-2 to H.264 (with Handbrake) and the results are even more superb. In fact, it looks like the lossless AVI. My theory is that because H.264 is superior, it sticks closer to the source--hence no visually noticeable loss.

[unclescoob]

AND THAT'S NOT ALL! I can also tap dance with a hemorrhoid-ridden semi-cranky monkey!!!

Watch:

RRRAa tata-tata -dada-rata ta ta dada!

[Mephesto]

MPEG-2 sucks so bad that it severely screws up some frames in high actions scenes at 40 Mbps. I would never re-encode with MPEG-2 at any bitrate.

[Cornucopia]

...Whereas others don't seem to have any problem with WELL-ENCODED MPEG2 (such as all the numerous cameras and editing systems that utilize and do fine with it).

MPEG2 is perfectly fine - at the right bitrate, and with the right encoder settings. It's just not AS EFFICIENT as MPEG4-ASP, nor MPEG4-AVC. MPEG1 is the same way, just less efficient still.

I could easily show you samples from all 4 that look identical in quality, but differ only in the bitrate required to achieve that quality. In fact, once I'm done with my move in August, I'd be happy to provide them.

Scott

[El Heggunte]

MPEG-2 sucks so bad that it severely screws up some frames in high actions scenes at 40 Mbps. I would never re-encode with MPEG-2 at any bitrate.

Are you sure you have ever used an adequate quantization matrix
for your casual "high-bitrate" MPEG-2 encodes?

According to manono, or rather, according to myself at least , the default MPEG-1/2 matrix
(the one whose intra-mode's first row reads 8, 16, 19, 22, etc.)
sucks royally:

https://forum.videohelp.com/threads/262456-mpeg2-quality-check?p=1568133&viewfull=1#post1568133

https://forum.videohelp.com/threads/240503-1PASS-CCE-quantizer-matrices?p=1418860&viewf...=1#post1418860

https://forum.videohelp.com/threads/270717-How-to-decide-what-custom-matrix-should-be-u...=1#post1622310

http://forum.doom9.org/showthread.php?p=759872#post759872