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Thread: ExtractStream and PlayStream failing on every sector in a DTivo

  1. #46
    Join Date
    Jan 2002
    Posts
    183
    Forgive the stupid question from the new guy, but...

    Anyone tried mpgtx -i to see what's in these streams?

    -Z

  2. #47
    Join Date
    Dec 2001
    Posts
    17
    logicTrAp: Thanks, that output helps a lot. I'm learning more and more about the true nature of MFS with every pass. It turns out that using masks of 0x3ffff and 0xfffff are only approximations of the real solutions. The 0x3ffff mask works best in many situations on the SA TiVos and the 0xfffff mask works best on many DTiVos.
    The real solution seems to be in the metadata in the MFS partition "headers". I found these structures which along with some code that uses them. With what I've learned already, I can tell that the FSID calculation can be done precisely on all systems.

    I'd like to update the experimental version to do just that, and have you all retest your systems and see if we have it right. That should take me a day or two.

    For those of you who would like to know more now, the real solution appears to be something like:
    Code:
    fsidHash = fsid * 67289 % totalSectorsOnAllInodeZones;
    virtualSector = fsidHash * 2;
    for(i = 0; ; i++) {
      if(zone[i].type == INODE_ZONE) {
        if(zone[i].sectors <= virtualSector) {
          virtualSector -= zone[i].sectors;
        } else {
          break;
        }
      }
    }
    sector = virtualSector + zone[i].start;
    partition = i;
    Turns out this works in both the SA and DTiVo cases, i.e. it's the Grand Unified Theory of TiVo MFS. But in order to do this, you need to have the list of zones and zone properties, and that's all found in the MFS "headers". Many thanks to tridge for showing the way! I may just end up using his code directly since it already does what we need. Is there a reason why ExtractStream doesn't use his code?

    -Ray
    Last edited by rwaldin; 01-08-2002 at 04:43 PM.

  3. #48
    Join Date
    Jul 2001
    Posts
    39
    Free pez dispenser for the squirrel that cracks this nut! Go guys..

    (sorry not any time to help out.. but atleast wanted to cheer )

  4. #49
    Join Date
    Nov 2001
    Posts
    730
    Hate to nominate the poor guy again, but sounds like another _Formula job.

    Dennis

  5. #50
    Join Date
    Dec 2001
    Location
    Greenbelt, MD
    Posts
    6
    Well, I've tried ExtractStreamDx1 on my Philips DTiVo hacked with 2.5Xtreme and though it runs without complaint, the files it produces resemble nothing more than random garbage. I'm certainly no mpeg stream expert, but I'd expect to see some common signature at the beginning each file. A hex dump shows no similarity between the start of any of the four files I've extracted.

    Has anyone found anything comprehensible in the output from ExtractStreamDx1? I'm worried that they have actually encrypted the tystream as someone suggested earlier.

    Prosaic

  6. #51
    Join Date
    Nov 2001
    Posts
    117
    I ran the new version aginst two diffrent streams. I compared the size of the output file vs the size that showlist.tcl said it should be and they were diffrent. I'm attatching the session log for reference. Eventhough the "nut" hasn't been fully cracked, roasted, diced and baked into a pie yet, I'm happy to see that tridge's work might lead us closer to our final goal. BTW I ran this on a Phillips DSR6000 running factory 2.0.1 and factory prom. Well at least I restored the system back to this state from my original backups. Backups don't leave home with out them.
    Did I do that...

  7. #52
    Join Date
    Sep 2001
    Posts
    889
    Your log is rather useless...

    You list several showings, none of which match the fsid that you extracted.

  8. #53
    Join Date
    Oct 2001
    Posts
    209
    Hey where is the latest modified extractstream?? I'm gonna try to pull some small segments off my tivo with PPP; lend a hand in this arena...

  9. #54
    Join Date
    Dec 2001
    Posts
    17
    ExtractStreamDx1, same as before, no changes yet.

    BTW, I've been playing around more and more with tridge's mfs progs and the mfs_export util seems to work fine on my DTivo. The output of
    Code:
    mfs_export fsid outfile
    is exactly the same as
    Code:
    ExtractStreamDx1 -s fsid > outfile
    I would imagine that mfs_export would work for SA Tivo as well. So why do we need ExtractStream again? Attached is a compiled copy of mfs_export...

    -Ray
    Last edited by rwaldin; 01-09-2002 at 07:45 PM.

  10. #55
    Join Date
    Dec 2001
    Posts
    17

    damn

    forgot the attachment again! Here's mfs_export...

  11. #56
    Join Date
    Jun 2001
    Posts
    3,108
    i have a dtivo running 2.5, but there are some shows left over from 2.0.1. i will try to use either the new extractstreamDX1 or the mfs_extract to get a pre-2.5 and a post-2.5 to see if they will be treated differently.

    btw: the above mfs_extract.zip is corrupt when i try to extract.
    Last edited by mrblack51; 01-09-2002 at 10:02 PM.

  12. #57
    Join Date
    Nov 2001
    Posts
    117
    I've bolded, raised the font size and colored the fsid I tested here for the hard of sight. (buba)
    Did I do that...

  13. #58
    Join Date
    Nov 2001
    Posts
    117
    I concur, I get bad crc when I extract mfs_export also. Can you put that up again.
    Did I do that...

  14. #59
    Join Date
    Sep 2001
    Posts
    889
    hmm.. I had just assumed that fsid refered to the parameter marked fsid.. silly me..

  15. #60
    Join Date
    Jan 2002
    Location
    Medford, MA
    Posts
    23
    I found the mfs_extract to be corrupt as well, but I pulled the source down out of CVS and recompiled it. You can get any of the binaries at http://www.chiappa.net/~chris/tivo/tridge
    tyc seems much happier converting these streams than the ExtractStream ones I've managed to get so far, and they play in vlc as well although it seems to get confused and play them at half speed or something. One odd thing - I extracted a show in 3 parts and sampeg doesn't seem to like the third piece, claiming it has a stream type of 0. Hrmmm...

    The principal advantage of getting a working ExtractStream would be that it can extract all of the fsids at once, and will also demplex the stream on the fly if you want.

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