What is the difference in the codecs? - Blu-ray Forum

Coltboy · 05-24-2007, 01:23 PM

I have been on here for a few months now and i need to understand the differences in the codecs. VC-1 MPeg-2,4 TrueHD and so on. i don;t mean to be stupid but it is a little confusing, can someone explain it to me. thank you

Just woud like to be better informed

haiku_aubade · 05-24-2007, 02:35 PM

MPEG 2/4 are video codecs used on Blu-rays
MPEG4/AVC uses a higher bandwidth, thus, is more superior over MPEG2
VC-1 is the video codec used on HD-DVD's

Dolby TrueHD and DTS HD-Master Audio (MS) are the new HD audio codecs.

Coltboy · 05-24-2007, 02:42 PM

thank you very much

theknub · 05-24-2007, 02:59 PM

haiku and coltboy,
all three codecs are (can be) used on blu-ray and hd-dvd. however, the majority of titles on hd-dvd have used the vc-1 codec. on blu-ray, mpeg-2 has been the most used codec with avc (mpeg 4) really starting to be used. avc and vc-1 were originallt developed as low bitrate codecs (less bits = smaller file size but with ability to look like a bigger file). vc-1 is a microsoft product while avc is part of the mpeg group. as is my understanding, vc-1 has some very curious similarities to avc but is different. the primary difference is that mpeg2 requires many more bits to really stretch it's legs and provide a hi-def encode while avc and vc-1 require less. this is why it has not been used (much?) on hd-dvd. the disc simply can not support the size needed for an mpeg2 encode and the audio track. with microsoft primarily backing hd-dvd, vc-1 has been the end all for that format. blu-ray on the other hand has seen a handful of vc-1 but mostly mpeg2 and avc.

the dts hd-ma, truehd and linear pcm are next gen audio formats. linear pcm is uncompressed (amazing) audio. truehd and dts hd-ma are lossless next gen compression methods that are supposed to sound like linear pcm but take up half the space.

theknub · 05-24-2007, 03:00 PM

damn you hdjk

i was typing my response...

Don Blish · 05-24-2007, 06:36 PM

In defence of mpeg2, I had read somewhere that at the quality levels HDTV viewers expect, AVC only has about a 20% bitrate or size advangage over mpeg2. I have no firsthand experience, but you can look at the several HDcameras now available to consumers in both AVDHD and HDV versions. HDV for 1080x1440 is mpeg2 at a constant 25megabits/sec. The AVCHD cameras have their best bit rates in the 8-12 range, and none of them apparently yield pictures as smooth and artifact free as HDV....according to camcorderinfo.com tests.

HDJK · 05-24-2007, 07:41 PM

Quote:

Originally Posted by theknub

damn you hdjk

i was typing my response...

It's all good. Some useful information in there that I didn't write.

desmond · 05-25-2007, 07:32 PM

Quote:

Originally Posted by theknub

the dts hd-ma, truehd and linear pcm are next gen audio formats. linear pcm is uncompressed (amazing) audio. truehd and dts hd-ma are lossless next gen compression methods that are supposed to sound like linear pcm but take up half the space.

Once uncpompressed True HD and DTS HD-MA become bit equivalent of LPCM. Compression is solely used to minimize storage requirements, there is no data loss. Hence there is no need for very extensive audio processing. You get amazing sound either way in a very cost effective manner.

theknub · 05-25-2007, 08:32 PM

Quote:

Originally Posted by desmond

Once uncpompressed True HD and DTS HD-MA become bit equivalent of LPCM. Compression is solely used to minimize storage requirements, there is no data loss. Hence there is no need for very extensive audio processing. You get amazing sound either way in a very cost effective manner.

umm, right. and the point?

HDJK · 05-24-2007, 02:46 PM

Quote:

Originally Posted by haiku_aubade

MPEG 2/4 are video codecs used on Blu-rays
MPEG4/AVC uses a higher bandwidth, thus, is more superior over MPEG2
VC-1 is the video codec used on HD-DVD's

Dolby TrueHD and DTS HD-Master Audio (MS) are the new HD audio codecs.

That's not entirely true. Both HD-DVD and Blu-ray support all three video codecs (as there are many Warner BDs with direct VC1 ports from HD-DVD).

AVC and VC1 don't 'use' a higher bandwith. They are more efficient and thus uses less space than Mpeg2 for a similar result.

Dolby TrueHD and DTS HD-Master Audio are losless codecs that (should) be equal to uncompressed PCM audio.

haiku_aubade · 05-24-2007, 02:49 PM

thank you for the correction

05-24-2007, 01:23 PM	#1
Coltboy Active Member Top ranked HT gallery Member since:Mar 2007 Location:OHIO Home Theater Gallery:72 Blu-ray collection:14 Blu-ray reviews:13	What is the difference in the codecs? I have been on here for a few months now and i need to understand the differences in the codecs. VC-1 MPeg-2,4 TrueHD and so on. i don;t mean to be stupid but it is a little confusing, can someone explain it to me. thank you Just woud like to be better informed

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05-24-2007, 02:35 PM	#2
haiku_aubade Active Member Member since:May 2007 Location:alpha centauri	MPEG 2/4 are video codecs used on Blu-rays MPEG4/AVC uses a higher bandwidth, thus, is more superior over MPEG2 VC-1 is the video codec used on HD-DVD's Dolby TrueHD and DTS HD-Master Audio (MS) are the new HD audio codecs.

05-24-2007, 02:42 PM	#3
Coltboy Active Member Top ranked HT gallery Member since:Mar 2007 Location:OHIO Home Theater Gallery:72 Blu-ray collection:14 Blu-ray reviews:13	thank you very much

05-24-2007, 02:59 PM	#4
theknub Blu-ray Guru Member since:May 2006	haiku and coltboy, all three codecs are (can be) used on blu-ray and hd-dvd. however, the majority of titles on hd-dvd have used the vc-1 codec. on blu-ray, mpeg-2 has been the most used codec with avc (mpeg 4) really starting to be used. avc and vc-1 were originallt developed as low bitrate codecs (less bits = smaller file size but with ability to look like a bigger file). vc-1 is a microsoft product while avc is part of the mpeg group. as is my understanding, vc-1 has some very curious similarities to avc but is different. the primary difference is that mpeg2 requires many more bits to really stretch it's legs and provide a hi-def encode while avc and vc-1 require less. this is why it has not been used (much?) on hd-dvd. the disc simply can not support the size needed for an mpeg2 encode and the audio track. with microsoft primarily backing hd-dvd, vc-1 has been the end all for that format. blu-ray on the other hand has seen a handful of vc-1 but mostly mpeg2 and avc. the dts hd-ma, truehd and linear pcm are next gen audio formats. linear pcm is uncompressed (amazing) audio. truehd and dts hd-ma are lossless next gen compression methods that are supposed to sound like linear pcm but take up half the space.

05-24-2007, 03:00 PM	#5
theknub Blu-ray Guru Member since:May 2006	damn you hdjk i was typing my response...

05-24-2007, 06:36 PM	#6
Don Blish Member Member since:Jun 2006 Location:Los Angeles	In defence of mpeg2, I had read somewhere that at the quality levels HDTV viewers expect, AVC only has about a 20% bitrate or size advangage over mpeg2. I have no firsthand experience, but you can look at the several HDcameras now available to consumers in both AVDHD and HDV versions. HDV for 1080x1440 is mpeg2 at a constant 25megabits/sec. The AVCHD cameras have their best bit rates in the 8-12 range, and none of them apparently yield pictures as smooth and artifact free as HDV....according to camcorderinfo.com tests.

05-24-2007, 02:49 PM	#11
haiku_aubade Active Member Member since:May 2007 Location:alpha centauri	thank you for the correction

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