The great Dreambox recording experiment

[señor ding dong]

Since getting my DM500c, I have been quite disappointed with its Direct Recording capabilities, or lack thereof. I have tried virtually all the available Enigma images on both clones and original boxes, I've tried different cable feeds, boosters, attenuators, various cams and tuner drivers, etc, and the results have ranged from barely acceptable to pathetically bad, with most recordings ending up with some sort of error along the way. The few Neutrino images that are available have generally fared better than the Enigma ones, and server based recording (Ngrab/DboxWinserver) has usually yielded fairly decent results, but still a far cry from the stability I had been used to on my old Dbox2.

In the interest of getting a clearer picture of the problem, I would like as many people as possible to volunteer to test a few recordings and post their results. I have attached a copy of MPEG2repair, which can be used to scan a TS file for errors, so the assessment won't be left up to the human eye. I would like to test recordings of 30 minutes or more, preferably more, but 30 minutes will do. If you could run a few of your recordings through MPEG2Repair and post the resulting txt file along with information about which channel, image, emu/cam and which tuner driver you're using, I would be extremely interested in seeing the results. Other worthwhile information would be the signal readings for the channel you're recording from and whether or not you're using any boosters or attenuators, and if you're recording to an external NAS, which protocol you're using.

Since the Sky Sports and Movie channels appear to be among the more troublesome channels for most people, I would prefer to see results from those channels, but other channels are welcome too. ;-)

Like I said, I have tested both clones and original boxes with almost identical results, but have not yet had the opportunity to do much in-depth testing on the new 600PVRs, but early indications are that the 600s do provide better recordings, but let's just check and make sure, so the more 600 owners I can get to play along the better.

Using MPEG2repair is simple. Just extract the attached RAR file, fire up mpeg2repair.exe, select your .ts file, click Find PID's, check Log Errors, press START, and off you go. In some case, you may have to manually select the audio PIDs. PID1 should usually do the trick. Depending on the size of your recording and your PC's CPU power, it shouldn't take more than a few minutes to scan the file and produce a txt log.

Thanks in advance to anyone who participates. There'll be a Snickers bar and a shiny space blanket at the finishing line.

*Snickers bar and shiny space blanket only available while stocks last

 

[Devilfish]

I'll definitely sort you out with a few results m8. After all the time and help you've put into the dreambox section it's the least I can do.

Hopefully have some results in a few days.

 

[scott-ayling]

ill see wat i can do fo you too mate just never record anythin usually nothin worth recording as everything is usually repeated anyway.But ill record anyway as i love playing abiut with the dreambox. i have the digitalworldz 1.6.5 image on my box.nightshift tonight and tomorow so will be either mon or tues before i post my results

 

[dc_uk]

Likewise, I'll try and get some results for you. See if we can find something out regarding the recording issue as i've had nothing but trouble too

 

[loady]

a pointer to a recording how to thread would be helpful as well.

 

[señor ding dong]

a pointer to a recording how to thread would be helpful as well.

When in doubt, look to the sticky...

"How Do I Setup A Mount for Direct Recording?"
http://www.digitalworldz.co.uk/forums/showthread.php?t=102266

 

[solster]

hey mate. im using Gemini 3.4 UK mod, GBox emu and old tuner, NAS Recording with CIFS, connection is only split once (one to modem one to dreambox) and with SLX Booster (argos). will run several tests for you and update this post as i do.... (got to rar them as they to big to post as txt)

-----------------------------------------------------------
07-06-12 - HTV - Britain Got Talent.ts.txt
SNR: 92%
AGC: 49%
BER: 80

comment: quality was top but it kept "glitching" every couple of seconds for some odd reason.
-----------------------------------------------------------
07-06-17 - HTV SW - Britain Got Talent.ts.txt.rar

same as previous just a different day (thought it might help you compare or what not)
-----------------------------------------------------------

 

[señor ding dong]

hey mate. im using Gemini 3.4 UK mod, GBox emu and old tuner. will run several tests for you and update this post as i do.... (got to rar them as they to big to post as txt)

07-06-12 - HTV - Britain Got Talent.ts.txt
SNR: 92%
AGC: 49%
BER: 80

comment: quality was top but it kept "glitching" every couple of seconds for some odd reason.

Not odd at all. As can be seen from the log file, this recording is full of errors, and some of the blocks of errors are absolute huge.

Thanks for taking the time to do this. It will be interesting to see if these results improve with other settings and/or channels.

 

[middlewingnut]

Top thread! I've got a few recordings that I'll check for you asap.

 

[simonk1969]

Three files attached the one dated 07-06-12 reports errors but when watched actuially appears perfect. The other two both report errors and when played back it has the effect of evry few seconds skipping a second or fraction of a second which makes it unwatchable !

I don't really know hwat I'm looking at in these logs so if someone could explain it that would be great.

 

[T4i]

I get the impression SNR is quite a big factor in recordings.

Streaming to PC also gives me wierd resutls, I can't stream ITV4 and some cartoon channels.

But can stream Sports 1/2/3 fine!

My IVT4 has a low SNR, as do some cartoons. But Sports 1/2/3 have the best signals for me.

 

[señor ding dong]

Three files attached the one dated 07-06-12 reports errors but when watched actuially appears perfect. The other two both report errors and when played back it has the effect of evry few seconds skipping a second or fraction of a second which makes it unwatchable !

I don't really know hwat I'm looking at in these logs so if someone could explain it that would be great.

There are many different things that can go wrong in an MPEG2 file, and anything that says "video error" in the log file is a problem. It will typically be missing data packets, which on playback will cause either image corruption, break-up or stuttering. The log file tells you where it happened, how many bytes and/or pictures slices were corrupted, as well as other techy information, but all that really matters is the magic word "video error", and you've got a lot of them. Instead of going through the file line by line, you can scroll down to the end for a summary, where it will say "x of x video frames found with errors." and how many bytes in total were corrupted.

Yours and Solster's log files are actually some of the worst I have seen. In your Two Pints recording, you have an astonishing 347 corrupted frames in a 30 minute recording. I usually get kind of annoyed if I have more than 5-10 errors in a 30 minute recording. On my Dbox2, it is rare to get even 1 or 2 errors per 30 minutes, and most recordings don't have any at all.

Even the Kickboxer recording, which you said appeared perfect, has 700 errors, albeit over the space of 2 hours, and in terms of corrupted bytes, on average it's not as bad as the others and would be less noticeable, but it's still a lot of errors.

Thanks for sharing your logs. Unfortunately, the ones posted so far actually paint a grimmer picture of Dreambox recordings than I had hoped for.

 

[señor ding dong]

I get the impression SNR is quite a big factor in recordings.

It would certainly seem like a logical assumption, and once the SNR is below a certain level, you're bound to get errors, but I have seen considerable differences in recording errors from channels with more or less identical signal readings, so I wouldn't say it was the only factor, though people have in the past suggested that signal readings in many, if not all images aren't all that accurate, and that they would be subject to weaknesses in the tuner hardware itself.

Streaming to PC also gives me wierd resutls, I can't stream ITV4 and some cartoon channels.

But can stream Sports 1/2/3 fine!

My IVT4 has a low SNR, as do some cartoons. But Sports 1/2/3 have the best signals for me.

Could I persuade you to maybe share a recording log or two from the Sports channels, as they seem to be the ones most people have problems with?

 

[T4i]

It would certainly seem like a logical assumption, and once the SNR is below a certain level, you're bound to get errors, but I have seen considerable differences in recording errors from channels with more or less identical signal readings, so I wouldn't say it was the only factor, though people have in the past suggested that signal readings in many, if not all images aren't all that accurate, and that they would be subject to weaknesses in the tuner hardware itself.

Could I persuade you to maybe share a recording log or two from the Sports channels, as they seem to be the ones most people have problems with?

No probs, will record tonight

 

[T4i]

- DIORJ 0.6 (New Tuner)
- Not sure which CAM it uses, MG or EVO

-----------------------------------------------------------
18th June 07 - Sky Sports 2 - British Superbikes.ts.txt
SNR: 95%
AGC: 41%
BER: 0
-----------------------------------------------------------

Main feed into Konig CATV amp, then a 2 way splitter (one into DB, other to upstairs splitter) then another 2 way split, then modem, then another 2 split and DB and Pace stb.

This is all done using the upstairs DB, so split 3 times.

 

[señor ding dong]

- DIORJ 0.6 (New Tuner)
- Not sure which CAM it uses, MG or EVO

-----------------------------------------------------------
18th June 07 - Sky Sports 2 - British Superbikes.ts.txt
SNR: 95%
AGC: 41%
BER: 0
-----------------------------------------------------------

Main feed into Konig CATV amp, then a 2 way splitter (one into DB, other to upstairs splitter) then another 2 way split, then modem, then another 2 split and DB and Pace stb.

This is all done using the upstairs DB, so split 3 times.

Yikes, this one was nearly as bad as simonk1969's Graham Norton recording. The reason I don't think it has a great deal to do with signal levels is that you said you feel your sports channels are very good, but it has also been my own experience that perfect stability doesn't mean perfect recordings, far from it. I seem to have a good signal myself. I never get any break-up or freezes at all. On the Dbox2, recording errors would always be visible during the "live" broadcast, but that doesn't seem to be the case with the Dreambox, which suggests there's something else going on. I have also had far more success with Neutrino images than any Enigma based image I have tried, and I've been through just about all of them.

Anyway, thanks for taking the time to share a log file.

 

[T4i]

- DIORJ 0.6 (New Tuner)
- Not sure which CAM it uses, MG or EVO

-----------------------------------------------------------
18th June 07 - BBC ONE - Look North_ Weather.ts.txt
SNR: 95%
AGC: 37%
BER: 0
-----------------------------------------------------------

 

[señor ding dong]

- DIORJ 0.6 (New Tuner)
- Not sure which CAM it uses, MG or EVO

-----------------------------------------------------------
18th June 07 - BBC ONE - Look North_ Weather.ts.txt
SNR: 95%
AGC: 37%
BER: 0
-----------------------------------------------------------

Thanks. With less than half the amount of errors, that one is considerably better than the first one, but it still has 341 frames with errors in just 28 minutes, which is very high, and the actual number of corrupted bytes is only marginally lower, so the errors are less frequent but more intense, for lack of a better description.

Like I said in my original post, I have tested a number of friends' boxes, and when added to the logs posted here so far, the results paint a depressing picture, certainly of the DM500's recording capabilities. I'd love to see some 600PVR recordings, though.

 

[frenchman]

I made a recording last night for about 30 mins and will run it through the scanner and post up in a bit. I also have a direct recording from my relook 200's which also has enigma running on it and does have some glitching that I will scan as well, the file is around 1gb so might take a while.

I think the problem is more related to Enigma than the hardware.

Frenchman

 

[señor ding dong]

I made a recording last night for about 30 mins and will run it through the scanner and post up in a bit. I also have a direct recording from my relook 200's which also has enigma running on it and does have some glitching that I will scan as well, the file is around 1gb so might take a while.

I think the problem is more related to Enigma than the hardware.

Yes, possibly. I've certainly been getting better results with the few Neutrino images that are available. I'd be very curious to see some 600 recordings, though, as the few snippets I have seen were quite encouraging.