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1st April 2002, 15:28 | #41 | Link | |
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Re: heres an example of an 800Mb 80minCD
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1st April 2002, 17:45 | #42 | Link |
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Tronic and Ingo, coders of the upcoming MCF file format have been looking into this as well. It seems a problem comes up when trying to extract the MCF data from the CDROM XA. Windows and Linux are unable to see the CDROM in a filesystem sort of way.
Anyone aware of some sort of driver hack or driver project that would allow the CDROM to be seen as a filesystem? It seems were close but some nasty obstacles keep jumping in the way.
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1st April 2002, 19:46 | #43 | Link |
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you are missing somethin,
that is to know if a given file format can work w/o error correction. mpg format works like a plain text file, if there is an error,you'll lose just one character or few characters, all the rest will be ok, unless you loose a part of the header. avis work like a program, if you loose one bit,you loose all. and it isnt just about the header, but along all the file. now,dunno exactly about SVCD,but VCD,that is 172kB/s(140video+28 audio)can last at max 64 minutes on a 650mb-74minutes CD, then its written in mode 1. The fact is that when there is audio mpeg files lose their magic, due to audio/video sync issues mpeg files too are easy to get corrupted. Es: virtual dub never fails to load a video only mpg,but very often fails to load mpgs with audio. thus you could have pcm audio or mpg video only in mode 2, dont think video+audio streams.....unless someone makes a better audiovideo syncronization.....and then some other writes a new burning option.... |
1st April 2002, 20:01 | #44 | Link |
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@movmasty
The error correction is understood by everyone in this thread. We can get around that issue just using the MCF file format or by other means. At issue is how to extract the data from a M2F2 CDROM type? According to Tronic, ISObuster is format specific.
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2nd April 2002, 07:37 | #48 | Link |
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i didn't miss that post movmasty and i used the word assumption..., anyway, i wanna try for myself what does it mean "without error correction" i.e. will it still be playable after 1 playback? 2 playbacks? 50/100/1000 whatever.
i wanna experiment, but i (as others afaik) haven't yet managed to put an arbitrary file on a svcd file format. avi |
2nd April 2002, 15:27 | #50 | Link |
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I thinked about this way of recording AVI's about one year ago.
But now, looking to my CD collection I must say that it is not worth. Many CD is hard to read, and without error correction it will be disaster after couple years... |
2nd April 2002, 15:53 | #51 | Link |
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Sorry for being late guys ... this happens if you dont check the 'General Section' in regular periods ... shame on me !
You may read these threads here http://www.powerdivx.com/phpbb2/viewtopic.php?t=367 and here http://forum.doom9.org/showthread.php?s=&threadid=18969 also, the subject was raised before a few times already. About 1300 MB CDs or even DVDs : using mode 2 form 2 will always give you more storage capacity, even if your CD is bigger !! A 1300 MB CD should well be able to give you up to 1500 MB then, so all your nice 2 CD rips will fit on 1 CD then ... So, here is some more input : 1. AVI : This subject was discussed really more than one time and as a matter of fact it seems that good old AVI format is not at all prepared for this ! I was told not only the header will be problematic in case of reading errors, the whole file can be messed with a few bits missing or being wrong on some place ... so it seems you had to do a complete hack for this, and with respect to Ogg and MCF standing outside the front door this is really not worth it IMHO. 2. Ogg : We havent got any clear response on this from Ogg dev team, but it seems even Ogg has some neat CRC in the format that would allow using it for mode 2 form 2 discs. It should be, always bare in mind it was designed for stremaing also. 3. MCF : MCF was defined with Adler32 error correction and is extremely forgiving if any bytes or even blocks are missing. It will be a wise thing though to write the header itself ( although there is a safety copy of the header at the end of each file ) in normal mode and only the data itself in mode 2 form 2 ... but we are implementing this in the basic specs, as well as the possibility to split the whole file into several portions ( like 2 - 4 CDs, whatever ). Please check the MCF specs, technical section, on http://mcf.sourceforge.net for more info. How to implement this : Well there is a very good working implementation for S-VCDs we could use. A few things have to be done though : - Create a program that can do CUE/BIN from a MCF file on HDD, so its ready to be burned with Nero/CDRDAO/EZ etc. ; this should respect the header specific mode burning, being well possible i was informed. - Implement reading support into the MCF parser or another DirectShowFilter, so MCF files can be played directly from disc ! Please note that reading S-VCDs is not a basic feature of any Windows OS ( not sure about 98SE/ME ) !!! A virgin Win2k installation can not read S-VCDs directly, only after installing WinDVD ( or whatever ) the OS gets these capabilities ! This is not true for VCDs it seems, at least on my box it is working to copy/read the data directly from the CD to HDD, maybe because i have old version of PowerDVD installed, dont know. - Create an extraction tool similar to VCDimager/VCDgear to be able to copy/read the data from disc to HDD. It is well possible it seems, but requires some work to be done. If anybody is interested in joining the MCF dev team for this purpose, please PM me here. |
2nd April 2002, 23:56 | #52 | Link |
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What we're currently going to do with MCF:
All our sectors are Mode 2 sectors with 2336 octets of user-data. Mode 2 sector structure: (total size 2352 o) -Sync (00 FF FF FF FF FF FF FF FF FF FF 00) (12 octets) -Minute/Second/Frame (3 octets) -Mode (02) (1 octet) -User data (2336 o) In our track, -Sector 0: MCF-CD Header (contains X1 and X2 + some other data). -Sectors 1 - X1: MCF (headers), with some kind of error _correction_. -Sectors X1 - X2: MCF (data), no error correction, just detection (per-sector + per-cluster). -Sectors X2 - END: MCF (headers), with ECC. This would give us even more storage space than SVCD has. It seems that there is no reason to include any filesystem on the disc. Writing stuff to a BIN-image is pretty easy. The only tricky part is calculating the ECC. Reading stuff from CD or image, without ECC, is REALLY easy. Reading with ECC is somewhat tricky. Todo: -Figure out how TOC works: how to instruct players on how to read our track. -Decide how to do that ECC. |
3rd April 2002, 02:25 | #53 | Link | |
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Quote:
old mpg1 is free,while you have to pay for mpg2. Would be easy to make one driver for both mpg1 and 2, but isnt done for commercial reasons. as avi mpg could contain almost every codec(and in fact the mpg1 format is very less simple than many think,old mpg1 drivers cant read many new mpg1) only you cant just add a dll with the new codec,but have to rewrite all the driver, so would be possible,i think,also to implement any mpg4 codec in a mpg1+2+4 or mpg1+4 driver, with the advantage that it will be supported immediately from existing players and editors. Last edited by movmasty; 3rd April 2002 at 16:30. |
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3rd April 2002, 12:52 | #54 | Link | |
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I'd be interested to leanr if the elecard MPEG2 decoder has the ability to read/parse S-VCDs also ... time to ask Blacksun about that i guess ... |
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3rd April 2002, 17:47 | #55 | Link | |
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I guess if it was only up to MS, Windows would be able to read & copy everything directly. |
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4th April 2002, 20:02 | #56 | Link |
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I see a potential problem... when Windows reads a DAT file linked to the Mode2/XA area, it appends a RIFF header at the start of the file. This header is not present in the Mode2 video track (I've tested it). Also, the file is being read in RAW mode, i.e. it contains a sector header (sync,addr, mode) as well as subheader and EDC, every 2352 bytes.
So if you burn, say, an AVI file in the second track and link it from the first ISO track, you'll end with a AVI file with an additional RIFF header attached to it and lots ot sector headers to play with. So any software reading this should bypass this extra data. This seems OS dependent (I don't know if Linux does the same when reading such files). Perhaps this is only related to "M" flag files... Any thoughts? |
4th April 2002, 20:20 | #57 | Link |
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The biggest point you guys are missing is that Windows reads those file systems because they are declared standards (Whitebook, Greenbook, Yellowbook, etc) with Philips for Compact Discs.
Putting anything besides Mpeg2 in the Data area of a SVCD disc violates the standard, and its very likely it won't work correctly. |
7th April 2002, 15:48 | #60 | Link |
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@oddball,
thanks mate, this is very helpful info .... by chance BlackSun has very good contact with the elecard guys ... so i know wht he has to ask them tomorrow !! BTW : TRonic could create first 800 MB MCF CDs recetnly ( test only ) and updated the MCF CD specs accordingly. Now its time to fix the header specs ... |
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