Does non-mod16 resolutions create less quality x264 videos???

Kostarum Rex Persia · 23rd November 2005, 03:30

Does it.I heard from one place that if I set mod 8 or mod 4 resolutions in x264 codec,I will get(at the end) less quality x264 video.

Can someone explain this to me.

Sirber · 23rd November 2005, 03:35

x264 add black bars to get to mod16, so it's harder in those area.

Kostarum Rex Persia · 23rd November 2005, 03:39

Yes,yes,but I ask for mod 8 or mod 4 resolutions.I never use so far mod 8 oe mod 4,so I akking this because I heard that non-mod16 resolutions crete less quality video.Is it true?

Sirber · 23rd November 2005, 04:33

read my post again...

akupenguin · 23rd November 2005, 05:46

They're not black. x264 replicates edge pixels (i.e. the same padding algorithm as is defined in the standard for motion compensation). But that doesn't change the answer.

omion · 23rd November 2005, 11:28

Internally, x264 will expand the frame to a mod-16 resolution (like aku said) so the codec will see (and compress) this resolution. The result of this is that it will compress about as well as the next higher mod-16 resolution.

This means that you'll be using more bits per (visible) pixel than if you had used the mod-16 version.

I'd call it more of a compressibility loss than a quality loss, as the same settings will get you the same quality between a mod-16 and a non-mod-16 video.

celtic_druid · 23rd November 2005, 12:32

A compressibility loss is a quality loss if you are trying to hit a given bitrate.

Kostarum Rex Persia · 23rd November 2005, 18:35

Ok,thanks guys.If anyone forget to tell something about this......

hitbit · 23rd November 2005, 20:55

Regarding non-mod16 x264 movies, anyone other than me had problems playing these files with ffdshow? (mplayer plays them fine)

Manao · 23rd November 2005, 21:10

if mplayer plays them fine, a recent ffdshow one should to. There were issues with older builds, but it has been fixed in libavcodec, so it should also be fixed in ffdshow

hitbit · 28th November 2005, 09:00

ffdshow plays them only if a resize to mod16 option (internal to ffdshow) is active. Strange, why this happens only with AVC?

23rd November 2005, 03:30	#1 \| Link
Kostarum Rex Persia Banned Join Date: May 2005 Location: Serbia Posts: 560	Does non-mod16 resolutions create less quality x264 videos??? Does it.I heard from one place that if I set mod 8 or mod 4 resolutions in x264 codec,I will get(at the end) less quality x264 video. Can someone explain this to me.

23rd November 2005, 03:35	#2 \| Link
Sirber retired developer Join Date: Oct 2002 Location: Canada Posts: 8,978	x264 add black bars to get to mod16, so it's harder in those area. __________________ Detritus Software

23rd November 2005, 04:33	#4 \| Link
Sirber retired developer Join Date: Oct 2002 Location: Canada Posts: 8,978	read my post again... __________________ Detritus Software

23rd November 2005, 11:28	#6 \| Link
omion Registered User Join Date: Nov 2003 Location: San Diego, CA Posts: 325	Internally, x264 will expand the frame to a mod-16 resolution (like aku said) so the codec will see (and compress) this resolution. The result of this is that it will compress about as well as the next higher mod-16 resolution. This means that you'll be using more bits per (visible) pixel than if you had used the mod-16 version. I'd call it more of a compressibility loss than a quality loss, as the same settings will get you the same quality between a mod-16 and a non-mod-16 video. __________________ "We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel, H2G2

23rd November 2005, 21:10	#10 \| Link
Manao Registered User Join Date: Jan 2002 Location: France Posts: 2,856	if mplayer plays them fine, a recent ffdshow one should to. There were issues with older builds, but it has been fixed in libavcodec, so it should also be fixed in ffdshow __________________ Masktools x86 & x64: Stable (2.0a48) AVCMatrices : Stable (1.3) Anisotool : Beta (1.0a5)

23rd November 2005, 03:39	#3 \| Link
Kostarum Rex Persia Banned Join Date: May 2005 Location: Serbia Posts: 560	Yes,yes,but I ask for mod 8 or mod 4 resolutions.I never use so far mod 8 oe mod 4,so I akking this because I heard that non-mod16 resolutions crete less quality video.Is it true?

23rd November 2005, 05:46	#5 \| Link
akupenguin x264 developer Join Date: Sep 2004 Posts: 2,392	They're not black. x264 replicates edge pixels (i.e. the same padding algorithm as is defined in the standard for motion compensation). But that doesn't change the answer.

23rd November 2005, 12:32	#7 \| Link
celtic_druid Registered User Join Date: Oct 2001 Location: Melbourne, Australia Posts: 2,171	A compressibility loss is a quality loss if you are trying to hit a given bitrate.

23rd November 2005, 18:35	#8 \| Link
Kostarum Rex Persia Banned Join Date: May 2005 Location: Serbia Posts: 560	Ok,thanks guys.If anyone forget to tell something about this......

23rd November 2005, 20:55	#9 \| Link
hitbit Registered User Join Date: Sep 2004 Posts: 76	Regarding non-mod16 x264 movies, anyone other than me had problems playing these files with ffdshow? (mplayer plays them fine)

28th November 2005, 09:00	#11 \| Link
hitbit Registered User Join Date: Sep 2004 Posts: 76	ffdshow plays them only if a resize to mod16 option (internal to ffdshow) is active. Strange, why this happens only with AVC?