Convert WMV2 video to h264 to save space, but without a quality loss?

[mkvbob]

I have a bunch of videos in WMV2, so I thought I could save some space by using a more high-tech format.

However, after experimenting with different h264 quality settings in MeGUI it seems like it's impossible to retain image quality (like the fine texture detail of surfaces, h264 just smudges it out) without having the converted h264 version ending up bigger than the original WMV2 source?

Am I doing something wrong here?

[poisondeathray]

Not possible

You will always lose some quality using a lossy format.

And if you use a lossless format , filesize will be huge

[jagabo]

In general, any time you compress with a lossy format you will get quality loss. But h.264 (especially x264) at the same size as WMV2 should look pretty good. You probably won't be able to go too much smaller without noticeable losses.

[johnharlin]

Well, you probably already know this but just make sure when you do the conversion that you have your settings set at the same frame size because if you go to a smaller frame size then yeah, you are going to get horrendous quality compared to the original. Often times, converters keep the frame setting you used previously or they may have a different default setting so just make sure it is the same frame size.

[hello_hello]

It probably depends too on the quality of the original video and how hard it is to compress. I've encoded old mpeg video in the past using Xvid and either not been able to reduce the file size much, or the file size actually increased if I wanted to maintain as much quality as possible.

If the source video is already highly compressed (and if the quality isn't great), you're basically asking a lossy encoder to compress it again without reducing the quality any further, which may not be possible while reducing the file size.

Have you tried using one of the slower x264 speed presets? Or changing the Tuning to something other than default (although that'll probably increase the file size). At a given quality setting you may be able to use a slower encoding preset to reduce the file size a little, but of course it'll take longer to encode.

[mkvbob]

Yeah, I used a custom preset called "Unrestricted-Insane" from http://forum.doom9.org/showthread.php?t=139765 and it did give noticeably better quality than the default presets at the same file-size, while taking about 10 minutes to encode 3 mins of 720x480. However, it didn't achieve the goal of producing source quality at a lesser size .

Well, you probably already know this but just make sure when you do the conversion that you have your settings set at the same frame size because if you go to a smaller frame size then yeah, you are going to get horrendous quality compared to the original. Often times, converters keep the frame setting you used previously or they may have a different default setting so just make sure it is the same frame size.

You mean the resolution? Should be the same.

[El Heggunte]

FWIW, H.264 is not the only format which is "more advanced" than WMV2

Before going to ``remux wmv2 into MKV´´, I think you should give a try to Xvid, WMV3 and VC-1

[mkvbob]

As far as I understand h264 using x264 is supposed to be the best though. Do you really think my goal could be achieved with something like xvid or vc1?

[El Heggunte]

Speaking in general, H.264 was designed to "compress TOO MUCH" , which means it will give us very-nice results WHEN the sources are VERY-CLEAN
OTOH, WMV3 and VC-1, besides compressing less than H.264, are substantially different from the formats of the "MPEG family".

[poisondeathray]

As far as I understand h264 using x264 is supposed to be the best though. Do you really think my goal could be achieved with something like xvid or vc1?

It is the best, by quite a significant margin, especially with x264. But you're comparing using a different generation (flawed analysis)

If you encoded the source video (the video BEFORE the wmv2 video), then you would get better results

To make comparisons valid, you would be encoding the wmv2 video again using wmv, or xvid or vc-1 - and in this case x264 will produce vastly superior results (but still not as good as the original video)


Fact: When you use lossy encoding, quality ALWAYS gets worse each generation

[Cornucopia]

Not THAT different. They're still a progression from earlier WMV codecs which in their day were forks of MPEG4-SP. So they still work primarily as DCT-based codecs (not wavelet-based, or other), just like MPEGs.

WMV3/VC-1 should give you the equivalent of DivX/Xvid. Meaning not as good quality (or not as good filesize) as h.264, but better than MPEG2.

Scott

[hello_hello]

Yeah, I used a custom preset called "Unrestricted-Insane" from http://forum.doom9.org/showthread.php?t=139765 and it did give noticeably better quality than the default presets at the same file-size, while taking about 10 minutes to encode 3 mins of 720x480. However, it didn't achieve the goal of producing source quality at a lesser size

Those presets are old and possibly outdated. I was recently involved in a discussion in that thread and as a result one of the mods added a warning regarding using those presets to the original post. In fact I think the discussion I was involved in was interleaved with your posts.
Not that the old presets don't work, but given x264 and MeGUI are constantly being developed and those presets are years old.....
I was actually referring to using x264's own speed presets rather than the old MeGUI ones. The x264 speed presets are supposed to negate the need for advanced encoder "tweaking" by the rest of us. Unless you really know what you're doing, I'd stick to the x264 speed presets.

I'm not guaranteeing dumping the old Sharktooth/MeGUI presets will give you smaller file sizes or better results, but I'd not use them any more without good reason. MeGUI now uses a target playback device when configuring the x264 encoder which was intended to replace those old presets. If you open the x264 configuration dialogue and reset it to defaults, try an encode with the default settings. Then use x264's own speed presets (medium is default, or there's slow, slower etc) to see if slower speed presets reduce the file size much. Or experiment with raising the CRF value until you notice a quality drop, then stick to the highest CRF value you're happy with. The file sizes will still vary according to how hard each video is to re-compress. I don't think you'll find a "magic" setting which will automatically reduce the output file size for a given quality.
If you want to produce a video which can be decoded by a video card (hardware decoding) choose DXVA as the target playback device. I generally stick to DXVA (all it does is enforce the use of High Profile, level 4.1) as it's the level supported by most of the current media playing devices such as MKV capable Bluray players, TVs with built in media players, tablets etc. Chances are by using the old unrestricted MeGUI preset you'll be producing a video you'll only be able to play on a PC.

Once you set up the encoder using x264's own speed presets and a target playback device etc you can save the setup as your own MeGUI preset..... and then I'd be tempted to delete the old Sharktooth ones.

PS Contrary to another poster's advice, I'd also experiment with reducing the resolution a little to reduce the file size if all else fails. Especially if the source isn't particularly sharp, often you can reduce the resolution (sometimes by a substantial amount) without any major quality drop. There's no rule. Obviously keeping the original resolution is ideal, but then again so too is keeping maximum quality. I'd prefer to reduce the resolution a little rather than reduce the quality too much, but it's just a matter of experimenting a bit (or a lot) to see what looks best.