Help with mpeg2 repair? [Archive]

Lester Burnham

20th July 2009, 12:00

Hi

I'm wondering if anybody has any advice - I use a DV cam to record workout / training (to help with technique, and spot problems) - mainly skipping / jump rope, and heavy bag work.

Once I've recorded it, I record it to DVD using my standalone DVD player, and DV-out from the cam to DV-in on the DVD recorder (used to have a firewire card, but removed it from my previous PC, and now I can't find it).

Tends to work OK, but sometimes I have issues with the odd disk and have to redo the recording.

I've found the most reliable method of getting the recording off the disk on to PC is to use ripit4me. Because otherwise, sometimes there's the odd CRC error, and ripit4me seems to tell DVD decrypter to insert dummy packets / sectors as and when.

On the odd recording and rip to PC, sometimes the vob files don't always play ball. On problematic ones, if I open them in VLC, it will always start playback part-way through, and not go / seek back to the bit from before it started playing.

In the past, I used to use PVAstrumento to fix some mpeg2 captures, and I own a copy of VideoReDo, but it's quickstream fix, nor file open will handle the troublesome files (says not a program stream, but I'm guessing it checks X amount from the start of the file, and if it doesn't find usable streams, aborts). I did use it's basic trim and copy function by guestimating the amount of bad video at the start of the file, once.

Is there any other tools that may help repair any problematic files? The last recording I made, I've still got the DVD copy, but I decided to record over the full tape, wondering if keep recording varying amounts to the tape was partially giving me problems.

Thanks in advance for any help.

Ghitulescu

20th July 2009, 15:33

If there are errors on the disk no ripper can help you. Use a disk reading program (a recovery tool), like ISO buster or ISO puzzle.
After copying the content on the HDD you can use any software you like to process the VOBs (or VRO or whatever extention they may have). Because now the files are error free and you don't need a MPEG2 fixing software but a DVD authoring one.

But this question has been answered to some weeks ago. :search:

Lester Burnham

20th July 2009, 15:53

If there are errors on the disk no ripper can help you.

Isn't that what some of the evolved rippers do, though - sort out engineered disk "faults"?

Use a disk reading program (a recovery tool), like ISO buster or ISO puzzle.

I have no issue, using ripit4me, getting the data onto my PC.

After copying the content on the HDD you can use any software you like to process the VOBs (or VRO or whatever extention they may have). Because now the files are error free and you don't need a MPEG2 fixing software but a DVD authoring one.

That's the problem (they are VOB files, btw) some of these files aren't error free, and in these cases, nothing I know will properly process them.

When they are problematic, VideoReDo won't open them. PVAstrumento won't process them. Nor will ProjectX. vob2mpg will, but the resultant mpeg is still as problematic as the original VOB(s) was.

I've tried mpeg2repair, restream and vcdgear, and none fix them, vcdgear (I think) managed to salvage some of the video from one of the files.

But this question has been answered to some weeks ago. :search:

How to repair mpeg2 files? Could you link to it, then, because I searched before posting.

Ghitulescu

20th July 2009, 21:48

Lester Burnham

20th July 2009, 23:01

Well, I thought you want to rip your own DVDRs. So far I know the ordinary people cannot protect their DVDs so if the recording went well then you'll have a compliant DVD. I simply not understand why you need rippers to have your own DVDRs copied onto HDD. Copy/Paste should suffice :)

In some cases, either the recording musn't be perfect, or an issue betwixt recorder and media.

Regardless, when it occurs, I don't want to spend real time re-recording it - as it tends to be daily recordings.

ripit4me always seems to get the files from the recorded (DVD+RW) OK. Though the FixVTS (or ripit4me's internal version) would often clear the VOB files.

ISo Buster can repeat the reading until the data is correct. I'm afraid this is not the case with RipItForMe or any other 1-click software or any other software not designed for bad media.

Whilst I get that ISO buster does something different from advanced rippers, ripit4me and others, do cope with intentionally "bad" media.

The files are Ok.

The problematic ripped files aren't.

I'm looking to see if there's any way to fix them.

I realise I could always redo them, but probably by the time that's been established, the next days workout has probably overwritten the source data on the DV tape.

You mix up some things one into another.

No I don't.

I know I've got the files on my PC's hard drive. And ripit4me (/ DVDdecrypter) believe they've done a sound rip (albeit by inserting dummy sectors on occasion).

The files should be Ok, however it might occur that the recorder couldn't write the data perfectly. This is not a case for a ripper but a case for a recovery software. A ripper copies intentionally wrong data, a recovery soft tries to recover the good data from a bad medium.

It could also be flaws in the recording process, as opposed to a writing / media problem.

Fixing mpeg files is often done when capturing mpeg TS from sources such as DVB.

Once the recovery software did its job you'll end with good files. Final point. Use authoring software, no need for repairing tools.

Authoring software isn't useful at this point, because I'm using the DVD recorder to go from DV tape -> mpeg.

I'm no stranger to authoring DVDs, and maybe I'll archive them to DVD (although more like convert to AVI for achiving purposes - I mean it's not like they need to be particularly high quality video.

Ghitulescu

21st July 2009, 08:22

Once more:

1. you have MiniDV tapes, a camcorder (or a DV deck), a PC with a [lost] firewire card and a DVD recorder with DV-in.
2. you want to convert these tapes into a DVD (one or more)
3. since you lost the PC card you connect the DV source with the DVD recorder through a firewire cable and let the DVD recorder command the DV source -> you end with a DVDR containing the clips from the tape.
4. somewhere a terrible error occured: the information on these DVDRs is no longer correct

Now, if the DVD recorders would write the media correctly but with errors in VOBs, I wonder who would be so stupid to buy them ;). Plus, they have to obey the DVD standard. Therefore, unless the DVD recorder is really broken, we have to assume that the VOBs are ok.
Secondly, the medium (DVDR). It really depends on how old is your DVD recorder, and on the manufacturer of both recorder and media. Because if these 2 items do not match each other a possible bad burn might occur.
Third. This is a bit more complicated. Some DVD recorder manufacturers do implement a strange scheme in writing the DVDRs, that's why you can't read directly the files on your computer (typically Panasonic). It's not a copy protection (actually it's a bit of), but the way the standard evolved. You need a special software to read the logic from the files and convert them to computer readable ones. See below for an example.

So, your problem is to make the files compliant to the software you intend to use (the simplest way: from DVD files obtain MPEG ones). Rippers are programmed for commercial DVDs, not for DVDRs produced by SAPs. They tend to think that if there is something they do not "understand" then this is a copy protection. This is why RipIt4Me "asks" for dummy sectors.

-=-
Example:
I own several DVD recorders, one of them is a Pioneer. It has 2 modi: DVD video and DVD-VR. The recordings in DVD-VR modus would yield a VRO file and some other small files that hold the description of the clips. All clips are joined together in this VRO file. It can be seen by most software players but only by the DVD players that bear the VR logo. This file can comprise clips of various DAR (16:9, 4:3) and SAR (720x,544x,480x576 etc). The burner inside is an old DVR-103, which is not really compatible with the modern 16x DVDRs. Sometimes it fires burning errors. What to do?

Copy the VRO and the accompanying files on the HDD using ISO buster or ISO puzzle. Then launch TMPG DVD Author on the files from the HDD. I have no problems at all. If I'm launching the TDA directly from the disk it might fire an error, because TDA reads only once a sector (windows copy has 3 retries, most rippers have a smart modus activated (skip defect sectors), but iso buster can retry till the doomsday if you click retry ;)).

Lester Burnham

21st July 2009, 20:00

Now, if the DVD recorders would write the media correctly but with errors in VOBs, I wonder who would be so stupid to buy them ;). Plus, they have to obey the DVD standard. Therefore, unless the DVD recorder is really broken, we have to assume that the VOBs are ok.

1. I didn't buy it fundamentally as a DVD recorder - I bought it because it was a multi-region DVD player, that also plays mpeg4 files. The recording thing was a bonus, but one that I have only really recently made use of.

2. I don't think it's so great to assume the VOBs are OK - there's the possibility that something (on occasion) isn't going to well in the recording, over DV-in, of the camcorders output.

In fairness to using them together, I've had a DV camcorder for some time, and the DVD recorder - neither was bought with any particular intention to use them together, I just happen to at the moment, for training purposes and progress.

Even on some rips / copies of the DVD, when no dummy sectors have needed to be inserted, I've had issues with some of the VOB files.

Ghitulescu

22nd July 2009, 08:01

1. I didn't buy it fundamentally as a DVD recorder - I bought it because it was a multi-region DVD player, that also plays mpeg4 files. The recording thing was a bonus, but one that I have only really recently made use of.

2. I don't think it's so great to assume the VOBs are OK - there's the possibility that something (on occasion) isn't going to well in the recording, over DV-in, of the camcorders output.

In fairness to using them together, I've had a DV camcorder for some time, and the DVD recorder - neither was bought with any particular intention to use them together, I just happen to at the moment, for training purposes and progress.

Even on some rips / copies of the DVD, when no dummy sectors have needed to be inserted, I've had issues with some of the VOB files.

2. if the DV tapes have certain defects, it would be transferred as image defects onto perfectly valid VOB files. If the defects are so big, it depends on your DVD/DV devices how it works, some recorders stops the recording on firewire discontinuities, some DV devices do not generate firewire discontinuities.
It's like watching VCDs on a FullHD TV set, the image looks like shit, however it's a perfect FullHD image (1920x1080 pixels by 50/60 Hz).
-=-
I gave you an advice, you refuse to follow it (it costs you nothing, iso puzzle is free, does not have an installer, no DLLs, no system alterations, no hidden keys in registry or other nasty things), so I'm out.

Lester Burnham

22nd July 2009, 19:22

2. if the DV tapes have certain defects, it would be transferred as image defects onto perfectly valid VOB files.

I'm not necessarily suggesting that the DV tapes have defects.

Why is it so difficult for you to accept the possibility that something may be going wrong in transport?

It happens all the time in broadcast mpeg, which is why there are mpeg fixers.

I gave you an advice, you refuse to follow it (it costs you nothing, iso puzzle is free, does not have an installer, no DLLs, no system alterations, no hidden keys in registry or other nasty things), so I'm out.

Your choice - but grateful though I am for your contribution - your advice doesn't help me fix the mpegs I have on my PC, which I cannot re-record, as the source has been overwritten from the DV tape - and indeed the DVD RW has been reused.

That's why I was asking for advice on mpeg2 "fixers".

Ghitulescu

23rd July 2009, 07:42

I'm not necessarily suggesting that the DV tapes have defects.

Why is it so difficult for you to accept the possibility that something may be going wrong in transport?

It happens all the time in broadcast mpeg, which is why there are mpeg fixers.

Your choice - but grateful though I am for your contribution - your advice doesn't help me fix the mpegs I have on my PC, which I cannot re-record, as the source has been overwritten from the DV tape - and indeed the DVD RW has been reused.

That's why I was asking for advice on mpeg2 "fixers".

Use my advice for the next time :)
-=-
It can't be that the "transport" went wrong, because it's on the wire (quite well insulated against electrical or EM interferences) and the protocol is designed also for transmission errors.
It is the responsability of the playing device to send correct data or to flag the stream for errors, however the stream itself is standard-compliant, electrically speaking. If the tape has errors, the image is corrupted, but the stream is still standard-compliant (otherwise you can't see the images).
On the other hand, broadcast transmissions are sent through a very unreliable medium (air or "ether") which path is intersected by lightnings, rain, solar storms, JumboJets, birds, kitchen mixers, etc. It's like doing a recording by mic or by a cable. You have interferences on the mic, but not (much less) on the cable.
-=-
All MPEG-2 repairers do what RipItForMe did, throw away the parts they did not understand -> glitches. Why don't you use the fixers you know? Because all are the same, that's why.

Lester Burnham

23rd July 2009, 20:44

It can't be that the "transport" went wrong, because it's on the wire (quite well insulated against electrical or EM interferences) and the protocol is designed also for transmission errors.

As it is for over the air.

Now whilst the carrier medium may introduced glitches in over the air transmissions, possible faults with the tape, or the recording on the tape can introduce similar glitches over the wire.

On the other hand, broadcast transmissions are sent through a very unreliable medium (air or "ether") which path is intersected by lightnings, rain, solar storms, JumboJets, birds, kitchen mixers, etc.

But the source is much more likely to be robust and without errors.

It's like doing a recording by mic or by a cable. You have interferences on the mic, but not (much less) on the cable.

Indeed - but not none with a cable, otherwise digital recording via cable (DV, optical audio, previously) wouldn't have the same need for error correction.

Guess what happened with optical recordings (to things like Minidisc) when there was problems with the transport?

Glitches in the recordings - sometimes merely creating gaps, or track breaks, sometimes ruining the recording.

All MPEG-2 repairers do what RipItForMe did, throw away the parts they did not understand -> glitches.

That's simply not true - all mpeg2 repairers don't just do that. Perhaps some mpeg4 / AVI fixers do, but that's certainly not true for what several of the mpeg2 repairers do.

hy don't you use the fixers you know? Because all are the same, that's why.

No, that's not why, and they're not all the same.

I have tried with all the methods I know - but none of them that I use will open the files, because they say they can't detect the stream.

VLC tends to be able to open them all, but struggles with some portions of the files, which is why I was wondering as to whether there were any tools other than that I was using (listed already in the thread) that would be worthy alternatives for the VOBs already on my PC that I cannot recreate, because the source has now been overwritten

Ghitulescu

24th July 2009, 08:18

Ok, you lost some footage. So what, you're not the only one, NASA did too (http://news.yahoo.com/s/ap/20090716/ap_on_sc/us_sci_moon_video/print). In the 80ies tons of celluloid movies have been burned to regain the storage space, now they try to find the surviving bits.
If you have the DV tapes you can rewrite the DVDRWs, if not just go ahead. Let the life go on! I assume that if the footage would have been lifesaving to you, you wouldn't overwritten it.
You can rewrite a DVDRW hundreds of times, but I would be careful about the DV tapes (while some pro say it's bad, most people report up to 5 reuses). Also keep in mind that a DVDRW needs at least one cycle in order to achieve its performance, it may very well be the case that the first recording is defective.
-=-
So, in the end, you gave me right: all the MPEG2 repairers are the same, none could read back the video stream ;)
-=-
PS:believe me, if something goes wrong from DV to DVDR, it's highly probable not the wire/transfer. If you can read the DVD with windows copy, then the errors are generated by the DV device, in which case you cannot do anything to recover them (it's like recording static - the recordings are ok, the information/content not) unless you have access to a Sony DVCAM (which can recover some badly written DV tapes). If you can't read the DVD with windows copy, then the DVDR is badly burned, you may try another reading device or use a recovery software. Only if the recovery software says I cannot do this anymore you need the use of a MPEG2 repairer, which as I said before, simply cuts out the defective portions.

Ghitulescu

24th July 2009, 08:21

You can always record straight to DVDR if you connect the camcorder through firewire to the DVD recorder. Should the camcorder not allow this (some do), use the analog connections, the quality is extremely good.

You overcome this way the tape. And localize the defect.

Lester Burnham

24th July 2009, 09:22

If you have the DV tapes you can rewrite the DVDRWs, if not just go ahead. Let the life go on! I assume that if the footage would have been lifesaving to you, you wouldn't overwritten it.

No, it's not critical.

That's not why I asked the question - I simply asked if there were any other alternative mpeg2 repairers to the one's I'm familiar with.

So, in the end, you gave me right: all the MPEG2 repairers are the same, none could read back the video stream ;)

No, that's incorrect.

1. I haven't tried all mpeg2 repairers - just the one's I'm familiar with - I posted here to see if any other forum members had advice on others they'd used.

2. They don't just work by removing chunks of the video. As I said, just because some mpeg4 / avi repairers work like that, doesn't mean that's how mpeg2 repairers tend to work.

If you can read the DVD with windows copy, then the errors are generated by the DV device, in which case you cannot do anything to recover them (it's like recording static - the recordings are ok, the information/content not)

Recording by DV isn't like recording static - it would be if I was using the analog connections, but recording by DV is purely in the digital domain.

Only if the recovery software says I cannot do this anymore you need the use of a MPEG2 repairer, which as I said before, simply cuts out the defective portions.

And I've told you before, and I'll tell you again, that is not all that mpeg2 repairers do. They may have to resort to that, but it's certainly not simply all that they try and do.

VideoReDo's quickstream fix isn't simply about cutting out chunks of video, nor is PVAStrumento, nor are others that I've tried.

Ghitulescu

24th July 2009, 10:49

You don't get it, do you? You cannot tell apart the package from the content?

A MPEG file has a header, irrespective of its format, be it a MPG file, a VOB one and so on. If this header is defect, no software in the world can repair the content of the file, especially if you used a DVD ripper that inserted "dummy sectors" in it. You may recover the header by copying it from the next valid MPEG header (luckily the headers in a MPEG streams repeat on and on in the stream), but you cannot recover the pictures/frames, they have been replaced by 0s (usually). So you're forced to cut out the defective content. Or to paint it again by hand. Your hand.

And what if the next header is equally broken (some DVD drives fire a series of defective sectors, even if only one is really defect)? What if finds an accidental header within the middle of an stored frame?

Even more, if the headers are defective, no player can play the file. Some smart ones try to find a valid header and starts the playing from there. A MPEG2 repair software has no better cards than a player. Finding a header that starts with 000000000001 in the middle of an image filled by a smart ripper with 00000000000 is not really the easiest task to do.

A further complication is the existence of GOPs. If the GOP header is damaged, it's extremely hard to reconstruct back the GOP.

You are smarter than the software. If you think you can do better, then open the VOBs in a HEX editor and reconstruct back the original "good" files you had, by hand. Because what you see in the HEX editor is exactly what the software sees. Do an experiment, load a BMP file in a HEX editor, modify one or more of the fields +10, +18, +28, and +30 and reload it in any image viewer. Try to do this blindly, because only you know that a certain combination makes a picture out of these 1s and 0s, for the software all combinations make a picture.

So if the guys of VideoReDo (apparently you know better than me how it works internally) couldn't do it, being nicely paid, having a job to do and probably access to NDA specifications, who else can do it?

May I cite from the MPEG2Repair page (link to soft here- http://www.free-codecs.com/download/MPEG2Repair.htm): it's designed not to improve the image but to remove them.

So next time, if you want to give a second chance to your files, don't use a ripper, use copy/paste - if it's ok then the files are good and you need no reparations. If not, then use a recovery software and replace the DVDRW. The possibility that the recorder wrote good VOBs with bad data is extremely low, almost impossible. If you want to see how firewire works, try to make the cable do a weak contact. If you want to see how a bad DV tapes goes into good VOBs use it with dirty heads.

Lester Burnham

24th July 2009, 11:08

A MPEG file has a header, irrespective of its format, be it a MPG file, a VOB one and so on. If this header is defect, no software in the world can repair the content of the file

Yes, an mpeg2 file has a header.

It also has packets, and within each packet is often information about the video.

But regardless - although you seem to want to bicker with me over every point on this, simply because your advice doesn't help the bits I was asking for or was trying to recover - the point is still valid - mpeg2 repairers are NOT all the same and don't ALL work by simply REMOVING video.

Perhaps SOME do, but not ALL.

Now I'm not saying that some can magically recreate data, where there is no data, all I'm saying is that not ALL mpeg2 repairers do so by simply removing video. They may resort to that, but that's not all they do.

Now we can bicker incessantly over you trying to get me to take on board your opinion, which doesn't help me, but you seem to want to foist - but all I really asked for, was whether there was anything else I could try to recover the mpeg2 files on my PC, that I can no longer recreate from source.

I already know and realise that perhaps some of the media (and perhaps DVD recorder) aren't the best, high-end equipment for doing what I'm doing - but then it's not that important to me that it is.

ALL I was trying to do was to see if there was anything else I could do to salvage that which I can't recreate.

So if there's nothing you can add to help me salvage those files I cannot recreate from source, but know that there's some usable video in there (because VLC will play most of it), then I'm not entirely sure who you are helping by seeking to carry on arguing about this?

I'm not claiming to be an expert in either mpeg2, or DV, but I'm not entirely ignorant or without any understanding of the subject, either.

Ghitulescu

24th July 2009, 12:24

Ok, sorry, no intention to do any harm.

I told you from the beginning that if your ripper "repaired" the data, then chances to recover the footage is very low. Even a non-compressed file, like a WAV, is dificult to be repaired if big chunks are missing or randomly inserted. Compressed files are infinitely more dificult to repair, without having hints (recovery data) at hand.

And I gave you an advice how I would proceed for the next time, to avoid this.

I also gave you an advice how to reliably extract the files off the DVD, because in your first post you mentioned that you still have the DVD, only the DV tapes were erased. Because if you properly recovered the files, you wouldn't have any longer the problem of MPEG-2 repairing.

I also keep the originals till the last phase, to be able to start over again, just in case.

Yes, I don't have a solution to MPEG-2 repairing, because I don't need any.

2Bdecided

24th July 2009, 13:58

Various stand-alone DVD recorders make discs that aren't quite right, and cause problems when copied into a PC (if they'll copy at all), while playing just fine on most DVD players.

A new Firewire card for your PC will cost less than £15. Go and buy one and save yourself time and hassle!

Cheers,
David.

Ghitulescu

24th July 2009, 15:15

Various stand-alone DVD recorders make discs that aren't quite right, and cause problems when copied into a PC
You need the correct software for them (maybe also a driver, if the disk is not recognised by windows). TMPG DVD author knows how to read them. And there are other commercial softwares that can do this, but I don't recall their names since I'm not using them. The common mistake is to use a DVD ripper on such disks.
(if they'll copy at all), while playing just fine on most DVD players.

That's a writing problem. Most people do throw any Walmart (sorry) disk in and expect miracles, while most cheap DVD-recorders usually use even less grade PC drives. A missmatch occurs and a bad burn appears. If the drive is used also for playing, mechanical missalignements occur and could cause problems (the PC drives tends to default to higher than 1x speeds with newer media, which in RT recordings means that the drive writes at 4x, stops, resumes (BurnProof) at 4x, stops again and so on- the recorded DVD has a lot of gaps and this might cause problems on some drives). SAPs usually have 1x optics (if they are not using a PC drive ) which are by far better than the PC drives.
My Pio 464 can read most of my bad burns (DVD-103 from my DVR-7000, the first DVDR(G) recorder ever) while I need serious help from ISO buster and my LG to read them back on PC.