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#41 | Link |
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Join Date: Dec 2013
Posts: 317
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Isnt most Divx/Xvid content on the internet derived from DVD ? I remember it was in the year ~2000. That just came about with people starting to re-encoding DVDs with the hacked Divx 3.11 Alpha codec in resolutions like 640x360. People could have used some Mpeg-2 encoder too but there was no one available for free I guess. MP3 started off the same, with some hacked Fraunhofer encoder and Napster. Ah, piracy... "Sure it looks bad, but at least it's small". Mpeg-2 video could have done this as well, SVCD being one popular standard.
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#42 | Link | ||
Registered User
Join Date: Aug 2009
Posts: 271
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Quote:
The real issue is that, according to the DVD-Video specs, only the 720x756/480 resolution can have the 16:9 flag, everything else (for example 352x288/240) can only be flagged as 4:3. Which is the real problem. If your content is 16:9, you have to use the 720x756/480 resolution (if you use the DVD-Video format), which means you have to use higher bitrates, which means you have to use at least 4GB for a half-decent picture. So, where was I wrong? As I said in my previous post, DVD-Video forces you to use the 720x756/480 resolution if you want widescreen (16:9). Quote:
First of all, SVCD doesn't do 16:9 anamorphic. Not reliably at least, aka with the players capable of signaling it properly (for 16:9 TVs) or putting black bars (for 4:3 TVs). So, you have to letterbox during authoring and manually crop/zoom in the TV's widescreen settings when viewing on a widescreen TV. DVD-Video only does widescreen at 720x756/480, which requires high bitrates (for the standards of the day, at least). And that's before we take into account the fact MPEG2 degrades much worse than MPEG4 ASP. Basically, it all comes down to this: Have you tried squeezing a 2-hour movie on an SVCD? Or even on 2 SVCDs? It's unwatchable, even on a CRT television. You have to go to 4GB (DVD) at minimum, which was considered a huge filesize back then. Meanwhile, a 2-hour movie on 2CDs with MPEG4 ASP at 640x360 offered acceptable quality (for the standards of the day, at least), and even 1CD was considered watchable. Now, why is MPEG4 ASP used today? The answer is it's pretty small (700MB or 1400MB) and plays on pre-H.264 players. Nobody will download a 4GB (or 4.38GB) MPEG2 file for their car DVD player or for their non-HD TV-DVD combo in the kitchen. At least that's what I get by looking at the availability online. And for their big screen TVs, they will download the H.264 version ![]() Last edited by kurkosdr; 14th August 2022 at 02:49. |
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#43 | Link |
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Join Date: Apr 2006
Posts: 121
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None of the existing MPEG-2 encoders that I'm aware of would encode to long GOPs, and would enforce a strict pattern of P/B frames that sometimes didn't even respect a scene change, leading to low quality. For playback on a computer you could always encode to square pixels, same as XviD, no?
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#45 | Link | |
Broadcast Encoder
Join Date: Nov 2013
Location: Royal Borough of Kensington & Chelsea, UK
Posts: 2,734
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Here:
720x576 is PAL anamorphic 720x480 is NTSC anamorphic both can be flagged either 4:3 or 16:9 and it's gonna be the player that will re-scale them on the fly. 'cause people don't wanna throw away their 2002-era players and that's just sad... Quote:
The MPEG-2 Libavcodec encoder allows you to set an arbitrary GOP, however by default it assigns waaaaaaaay too many bits to the Intra, thus bit-starving P and B and the result is just... very poor. x262 doesn't support all interlaced chroma sampling modes as it was a work-in-progress encoder and unfortunately it stayed that way 'cause it has been abandoned eons ago, so... nope (and I know 'cause I begged the creator to keep going back then). |
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#46 | Link | |
Registered User
Join Date: Aug 2009
Posts: 271
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Quote:
Yeah, but nothing you or me can do about it, right? Also, things like car DVD players can't be easily upgraded. |
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#47 | Link | ||
Broadcast Encoder
Join Date: Nov 2013
Location: Royal Borough of Kensington & Chelsea, UK
Posts: 2,734
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As a broke person trying to save money, wishing to get on the property ladder and become a home owner one day, I drive a poor-people car, so a 2009 Nissan Micra where everything is analog and I had to buy a bluetooth to jack adapter to even use my phone... eheheheheh
Anyway, my father's car, a Mitsubishi, does indeed have a DVD player which reads MPEG-2 with either MP2 or AC3 audio, but my parents have never ever used it 'cause due to silly Italian laws they're not allowed to use it while driving as it might distract the driver (even if he's not looking at it at all). The Italian firmware made it so that if you're driving, it won't play and it will tell you that the playback will resume once the car stops, thus making it completely useless, 'cause let's face it, who in the world would sit in his car, in a car park, to watch a movie on a small screen? xD Quote:
DVD 720x480 flagged as 4:3 will be rescaled to 640x480 DVD 720x480 flagged as 16:9 will be rescaled to 848x480 with those being MPEG-2. Now, if you re-encode in xvid, you can toss away the ugly anamorphic thing and re-encode to a proper 1.77 (so 16:9) or 1.33 (so 4:3) and your argument stands, but for 4:3 'cause 640x480 4:3 1.33 is smaller than 720x480 anamorphic flagged 4:3, so you save space, but it doesn't apply for 16:9 'cause 848x480 16:9 1.77 is larger than 720x480 anamorphic :P (I don't wanna be pedantic, I got what you're trying to say, but you know this forum is read by thousands of people every day, so I like to clarify things for people who will read it in the future ![]() True, in general, if you compare apples with apples. In the case of DVDs, though, you have MPEG-2 25i or 30i which are generally deinterlaced before being re-encoded to xvid. Even though xvid is better than MPEG-2, we should note that encoding an interlaced source takes less bitrate than encoding a progressive source, if the same codec is used. In other words, if I were to use MPEG-2 to encode the same source, but one time progressive and one time interlaced, the latter would take less bitrate. Still, given that xvid is better than MPEG-2, it will still be able to yield an advantage even if it's progressive. Quote:
(I think it's widely used across the world, but if you don't know it's an ancient latin sentence used during the Roman Empire and you can find the meaning on Wikipedia) Last edited by FranceBB; 14th August 2022 at 21:01. |
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#48 | Link |
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Join Date: Aug 2009
Posts: 271
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Nobody encodes Divx avi in 848x480 and most pre-H.264 devices out there won't even play it (because it's beyond the maximum resolution allowed by the "Divx Home Theater" profile, which is what those devices implement). Most widescreen Divx AVI files are 640x360, which is substantially less pixels than the 720x480 minimum resolution that DVD-Video mandates if you want to have anamorphic widescreen. Coupled with the fact MPEG4 ASP degrades less bad than MPEG2, it allows for substantial bitrate savings (for example, an entire movie on 1400MB or 700MB), without the sea of artifacts you would encounter if you targeted such filesizes on DVD-Video.
BTW, don't get me wrong, I wish more stuff was made available as 4GB, 4.38GB, or even 7.96GB DVD-video for people with old devices, but that's not what I am seeing around. Most stuff out here is either Divx avi (700MB or 1400MB) or H.264 (MKV/MP4). Last edited by kurkosdr; 15th August 2022 at 14:12. |
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#49 | Link |
Registered User
Join Date: Dec 2013
Posts: 317
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Here are some Tears of Steel 720x300 encodes:
https://drive.google.com/drive/folde...UW?usp=sharing Mpeg2 and Mpeg4 look pretty equal to me. Last edited by rwill; 15th August 2022 at 18:47. |
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#50 | Link | |
Broadcast Encoder
Join Date: Nov 2013
Location: Royal Borough of Kensington & Chelsea, UK
Posts: 2,734
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Quote:
I took a look and yeah, I saw old ancient SD 4:3 encodes as 640x480 and my oooooooooooold SD 16:9 xvid encodes as 704x396 so that they were gonna stay within the profile constraint. To be fair, I should have remembered it given that I was one of the people who encoded in 640x480 and 704x396 in 2006-2007 for the Italian """branch""" of ADC-Elites (which then turned into OPF-Italia), but I forgot... it's been ages ago... Last edited by FranceBB; 17th August 2022 at 21:32. |
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#51 | Link | |
Registered User
Join Date: Aug 2009
Posts: 271
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Quote:
Also, the MPEG4 ASP looks better to me, and there is no mention of PSNR and SSIM either (can't be bothered to track down an uncompressed copy of the clip to do it myself, sorry). PS: It would seem weird to me that MPEG would go through all the effort of defining MPEG4 ASP and breaking compatibility with MPEG2 without at least some kind of significant improvement in the coding tools offered. Last edited by kurkosdr; 30th August 2022 at 19:34. |
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#52 | Link | |
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Join Date: Dec 2013
Posts: 317
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Quote:
Encoder and configuration used, of course I used the best Mpeg2 and Mpeg4 encoder I had available with the best settings I could come up with. That says it all I think. ... ... ... ... Ok maybe not... I used xvid_encraw which reports Code:
xvidcore build version: xvid-1.3.7 Bitstream version: 1.3.7 Configuration was: Code:
./xvid_encraw.exe -i tos_720x300_8b.yuv -type 0 -csp i420 -w 720 -h 300 -framerate 24.0 -bitrate 900 -pass1 -full1pass -max_key_interval 300 -quality 6 -vhqmode 4 -bvhq -masking 2 ./xvid_encraw.exe -i tos_720x300_8b.yuv -type 0 -csp i420 -w 720 -h 300 -framerate 24.0 -bitrate 900 -pass2 -max_key_interval 300 -quality 6 -vhqmode 4 -bvhq -masking 2 -o mpeg4.m4v ./y262.exe -in tos_720x300_8b.yuv -size 720 300 -threads 1 2 -profile main -level high -chromaf 420 -rcmode 1 -mpout stats.p1 -bitrate 900 -vbvrate 2000 -vbv 600 -quant 3 -quality 100 -frcode 2 -arinfo 1 -nump 18 -numb 2 -flatmat -videoformat 709 ./y262.exe -in tos_720x300_8b.yuv -size 720 300 -threads 1 2 -profile main -level high -chromaf 420 -rcmode 2 -mpin stats.p1 -mpout stats.p2 -bitrate 900 -vbvrate 2000 -vbv 600 -quant 3 -quality 100 -frcode 2 -arinfo 1 -nump 18 -numb 2 -flatmat -videoformat 709 ./y262.exe -in tos_720x300_8b.yuv -size 720 300 -threads 1 2 -profile main -level high -chromaf 420 -rcmode 2 -mpin stats.p2 -mpout stats.p3 -bitrate 900 -vbvrate 2000 -vbv 600 -quant 3 -quality 100 -frcode 2 -arinfo 1 -nump 18 -numb 2 -flatmat -videoformat 709 -out mpeg2.m2v Its scaling was done with some ffmpeg version with such a filter: "-filter:v scale=720x300". *edit* Its also telling that you make broad claims about the quality of 'Mpeg2' and 'Mpeg4' without mentioning encoder and configuration as well but complain about them missing when others disagree with your claims. Oh and the Mpeg2 video looks better to me. Last edited by rwill; 30th August 2022 at 20:06. |
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#53 | Link | |
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Join Date: Jan 2015
Posts: 1,016
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#54 | Link | |
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Join Date: Aug 2018
Posts: 21
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#56 | Link | |
Moderator
![]() Join Date: Jan 2006
Location: Portland, OR
Posts: 4,653
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Quote:
Dark Shikari had a great insightful post about the design defects in p2 ASP somewhere I can't find. A couple issues I recall is that the requirement that adaptive quantization go up and down by even numbers relative to a previously determined frame QP was a challenge and annoying to optimize. And Global Motion Compensation could really only save something like 1 bit per frame. Hopefully someone else can dredge it up. The broadcast market back then is what sold encoders, and therefore drove encoder development. MPEG imagined a big competitive ecosystem of vendors trying to squeeze out an extra 1% here and there to win contracts. That's what helped make MPEG-2 as good as it was, and later provided the many years of continuous improvement of H.264 and HEVC. MPEG-4 Pt 2 never got that kind of love, both due to, and a cause of, its relatively small paying market. Also, the streaming market back then was dominated by the proprietary QuickTime, Windows Media, and RealVideo. By the time they had had robust Pt 2 support, better codecs were available. Lastly, as it was pretty obvious that Pt2 was in trouble, H.264 (MPEG-4 Pt 10) development was accelerated and arrived a lot sooner than the typical 10 year gap between major MPEG codecs, had obviously superior compression efficiency, and had a simple licensing regime. That's what broadcasters targeted, and what the encoder vendors all pivoted to competing on. The commercial market for H.264 encoders was quickly 100x bigger than the Pt 2 market ever was, which funded a lot of encoder developers. And then x264 happened with a remarkably brilliant set of developers and a big global audience competing on encoding fast and beautifully and providing a much broader base of feedback and fine tuning than any encoder before it ever got. It's weird to think that traditional codec development back then didn't even look at animation content! |
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#57 | Link | |
HeartlessS Usurer
Join Date: Dec 2009
Location: Over the rainbow
Posts: 10,877
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Perhaps amongst this lot Code:
"Dark Shikari" NEAR ("ASP" AND ("p2" OR "part 2")) site:forum.doom9.org amend if you remember better search stuff EDIT: There is this post by bond (but not on defects), MPEG-4 ASP Information, What is MPEG-4? https://forum.doom9.org/showthread.php?t=73022
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I sometimes post sober. StainlessS@MediaFire ::: AND/OR ::: StainlessS@SendSpace "Some infinities are bigger than other infinities", but how many of them are infinitely bigger ??? Last edited by StainlessS; 19th October 2022 at 00:07. |
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#58 | Link | |
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Join Date: Aug 2018
Posts: 21
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#59 | Link |
Broadcast Encoder
Join Date: Nov 2013
Location: Royal Borough of Kensington & Chelsea, UK
Posts: 2,734
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Great piece of history indeed by our Ben.
![]() If there's someone I'd point my finger against (as an "antagonist") in history that would be Sony and their MPEG-2 pursuit 'till the bitter end. If it wasn't for Sony, MPEG-2 would have been dead in the water, but after the bitter disappointment of MPEG-4 ASP (i.e XVID) in 2001, most broadcasters didn't gamble with MPEG-4 Part 10 (i.e H.264) in 2004 for SD contents (720x480 29,970i - 720x576 25i) and decided to stick with MPEG-2. Back then, formats like IMX50 based on MPEG-2 All Intra 50 Mbit/s 4:2:2 were popular for SD files. In 2006, as little as 2 years after H.264 was introduced, the world moved to HD (and then FULL HD) and Sony made the XDCAM set of standard which is essentially MPEG-2 for both HD and FULL HD. Guess what happened? Many companies wanted "stability" and adopted it instead of H.264, but that was a big, big mistake. As result, most broadcasters are still using MPEG-2 for FULL HD contents to this very day and are hog-tied to this ancient, no longer supported, unoptimized codec with banding problems and what not. If Sony didn't do this, the world would have moved to H.264 for HD and FULL HD and MPEG-2 would have been dead by now. Last edited by FranceBB; 26th October 2022 at 16:41. |
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#60 | Link | |
Lost my old account :(
Join Date: Jul 2017
Posts: 321
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I think its crazy that the "smallest" viable house format for UHD XAVC-I Class300 is 500Mbps (50fps mode for pal regions), thats a 10x increase from xdcam 50! Tbh thats absurd given that mpeg-2 is over two decades old, and we still cant "save" space in the broadcasting world. This makes transitions to things like 1080p and 2160p very expensive to migrate to, so most just stick to 1080i/XDCAM. I tried to explain this to management when calculating on on storage cost for UHD migration, cause they couldnt understand why UHD would take up more than 4x than our old XDCAM format. It also doesnt help that that hw-decode and encode of 10bit 4:2:2 formats is abysmal. Like it would make so much sense for a AVC/HEVC mezz standard to also have good hw support in gpu-solutions, without the need for expensive purpose built acc-cards. If there were full out support in qsync/nvenc/VCE and implemented in a broad amount of applactions as NLEs etc for fast encode and decode I think it would accelerate adoption alot. It would also lower requirement for realtime ingest a lot. Last edited by excellentswordfight; 7th November 2022 at 13:41. |
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