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Old 8th August 2009, 01:59   #1  |  Link
iffybob
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Hardware Mpeg Encoders

Ok over the last few weeks I had a thread going about encoding DBVt to avis and mpegs, still not there on complete understanding, (mostley in my confidence in whats happening, there nothing like encoding 2 hours of video and finding the sound sync out or drifts ), but I have had a lot of help here even if some of it was just an idea or question to follow up that lead to better understanding on my part, thank you to all of those people.

But to find out your encoding "went wrong", takes time, both to encode and to watch through to find any errors.

so I have a 2.8Ghz P4, with 333Mhz Ram, to upgrade the memory I need to upagrade the board, if I upgrade the board I need, RAM, a new Graphics and sound cards, probley a new HD, or to put it another way , "A new computer", which I cant afford at this time.

So I thought, "Hardware encoder", dedicated hardware "can" run 10 times softeware for a given task.

So a "Google" later , where are they ?, I can find Analoge/VCR to Mpeg converters, I have already a Pinical DVC130, it hardware encodes,though I find if I run it without background rendering on, it produces a low bitrate mpeg2 stream, and if I process the file to a higher bit rate, it just re-encodes using "software", umm.

I can understand, that decoding with all the codecs and there variations, which I came across in files I have that decoding is a problem, but to produce a small set of standardised say DVD Mpeg streams, should not be.

To sumerise this idea
PC decode -output to-> Hardware encode -output to-> PC harddisk file.

A few years ago, there was an artical on the BBCs "Click" programe run on "BBC New 24" channel. They showed a USB device in development, that encoded using hardware and the guys said they were getting good results, I cannt find any reference to this anywhere even on the BBC web site.

On the afore mentioned search I also found servalence equipment, but the mpeg encoders took an analoge video source, and a few componant level moduals, not for a PC that did Mpeg encoding.

Is it just that with current PC processor speeds, (Possibly the newish graphics processors/number chrunchers, and these being made available to the programmer and not just the video memory) and the variations in codec in/ouput the hardware developers just dont see the point.

I wish to be enlightend
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Old 8th August 2009, 02:22   #2  |  Link
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Better to figure out how you've screwed up your processing chain to destroy AV sync.

Good HW encoders are very expensive, and cheap ones you wouldn't want to use.
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Old 8th August 2009, 02:42   #3  |  Link
iffybob
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I know at which point my AV sync messes up, bad arial signal ( signal reflections due to location and local interference ),

mostly the odd audio drop here and there that add up, just need to find find a "reliable" and "consistant" way to get rid of the variations,
without having to view every thing I do before deleteing the scource.

I bin out of following the computer thing for over 10 years now, just recently restarted, so Im doing a lot of cathing up.

I remember back when even, there were ISA cards that did mpeg hardware encoding, thought I cant remember Mpeg1 or Mpeg2, or at what resolutions.

I also "assumed" that my USB video encoder worked as follows,

Analogue Video (Composite or S-Video in my case) ---> Capture Frame Buffer ---->Mpeg2 Encoder--->USB interface.

and an alternative would be.

PC Frame Decoder --> USB -->Frame Buffer ---->Mpeg2 Encoder--->USB interface.

and that given the former the later would not be hard to implament.... I have been known to b wrong though.
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Old 8th August 2009, 03:49   #4  |  Link
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If you are starting off with a MPEG2 file off air then the next step before anything else is to eliminate any errors as much as possible. The best tool for this is ProjectX using the Demux option (this is the ONLY option that cleans up the signal) You then end up with a video file an audio file (maybe 2) and a subtitles srt file (if you put the teletxt page number in the presettings) As it process's the file you will see the errors on screen. See my signature for a link to a wiki I wrote on ProjectX, although it is for the Australian DVB system the settings will remain the same for UK. Another program to try is MPEGStreamclip, it has a fix file menu item and has the advantage of producing a straight forward MPEG2 PS file if you wish. Both programs are free. In reality dealing with video files you need a new computer with good quality memory and adequate hard disk capacity. Once you have a DVD conforming MPEG2 file you can either author it to DVD or use AutoGK to make a DivX or Xvid avi file. There are a number of other programs you could try. BTW a hardware solution is going to cost as much as a new computer assuming you select something worthwhile.
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Old 9th August 2009, 19:21   #5  |  Link
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Neuron2 is right.

DVB-T is already encoded with expensive (and good) HW encoders. You can't have the same quality in one pass with any SW encoders.

Improve your reception, it can be done so easily, and quite cheap.

But if you insist, buy yourself a DVD-recorder, some have DVB-T. And use DVD+-RWs. However, having reception problems, a DVD-recorder would have the same bad reception.
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Old 9th August 2009, 20:20   #6  |  Link
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Iffybob, have to agree with other posters on how best to spend your money.

You appear to be looking at hardware ways to circumvent the problem of dropped packets affecting AV synchronisation. That is treating the symptoms, not curing the disease!

Have you considered an aerial upgrade? I'm in Wombwell (you can't be far away!) and got all my DVB-T reception woes fixed with a new aerial for 90 fitted! The digital switchover will help considerably - digital signals are currently attenuated to prevent interference on analogue broadcasts. Once the analogue broadcasts are switched off, digital muxes will be broadcast at much higher power. Sadly, since we have to wait until September 2011 for the Emley Moor transmitter to stop broadcasting analogue I think a new aerial is a must for you.

Since we got ours I can record direct to PC from from a USB DVB-T receiver (which cost me about 12), demux in ProjectX, load the streams into Avidemux, crop and resize if necessary and encode to x264 for archiving. No problems with sync at all.
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Old 9th August 2009, 21:26   #7  |  Link
iffybob
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I have another thread on here titled "DVBt to AVI, aspect ratio", in which are decused many of the options I have.

My purpose of writing the inital post was " What happened to the Tech", I understand that a mega cpu and memory IS the best solution to video encoding, and the newer graphics pipline processors will speed things up a lot, but when a thing becomes a long standing standard ie "DVD-Mpeg2" for example that takes a lot of cpu time, the hardware is normaly a logical step, and I did not see that on my searches, thought I may be missing somthing.

"My excuse"
I have been out of the computer biz for about over 10 years, and doing a lot of catching up and only recently got the internet, a lot of data, and many dead ends, its taking time to catch up.

I first looked at projectX, and found the forum was in German, which I dont speak let alone read, but I will look at the other, links Ive been given, thank you.

I live in rented flat just outside town center Doncaster, so I cant fit an outside arial, but I do live at the top of a 3 story house, however as I said I have problems with interference, and signal reflections, there is a strip approx 1 meter wide that intersects the room where there are no reflections, but the signals not great, there for this is fed into an arial distribution amplifyer ( 1 input, 7 outputs), but it is a wide band TV/FM amplifyer, so no daisy chaining the signal, all pluged into a mains filter.

Also because there are 8 flats in this house, 7 next door, etc, there are a lot of mobile phones, micowaves, and flouresent(?) lights, water heaters, hair dryers etc, besides taxis and emergency services radios

I am going to fit a better and more appropriate arial, and have had a quick look to see if there any D-TV frequency band-pass filters available. ( money is an issue )

I think in some way I knew the answers to my questions, but I like to be sure before I move forward, and many of the people here are way more informed than I am.

Cheers every body, and thank you.
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Old 10th August 2009, 18:03   #8  |  Link
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Quote:
Originally Posted by iffybob View Post
I first looked at projectX, and found the forum was in German, which I dont speak let alone read, but I will look at the other, links Ive been given, thank you.
translate.google.com works very well, and I know that because I speak 5 languages. It was a big surprise to me.
Quote:
I live in rented flat just outside town center Doncaster, so I cant fit an outside arial, but I do live at the top of a 3 story house, however as I said I have problems with interference, and signal reflections, there is a strip approx 1 meter wide that intersects the room where there are no reflections, but the signals not great, there for this is fed into an arial distribution amplifyer ( 1 input, 7 outputs), but it is a wide band TV/FM amplifyer, so no daisy chaining the signal, all pluged into a mains filter.
That's plain wrong. As I was told by a colleague that works in the field of RF antennas (adaptation, propagation and so on), in an urban zone (many obstacles) it's the reflection that makes the reception possible. The silicon receiver in any DVB-T device can separate the main signal from it's reflections. You can't have ghosting like in the analog era. You may only have pixelation, if there is not enough data to feed the decoder.
Quote:
Also because there are 8 flats in this house, 7 next door, etc, there are a lot of mobile phones, micowaves, and flouresent(?) lights, water heaters, hair dryers etc, besides taxis and emergency services radios
I said you before, these "items" work in different spectral bands - and this is not to let you have a nice clean image on your TV, but to prevent any misfunctions of the police communications equipment due to civil broadcasts.

Mobile phones go 1800, microwaves are 2530 and so on.
Quote:
I am going to fit a better and more appropriate arial, and have had a quick look to see if there any D-TV frequency band-pass filters available. ( money is an issue )
That's the move. I think 50-80 for a "real" DVBT antenna (with amplifier, like Kathrein) is cheaper than a new PC not to count the time spent and the electricity on the long run.
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Old 10th August 2009, 19:59   #9  |  Link
iffybob
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The signal reflections I was refering to gave ghost inamges on the old analogue TV, I was getting 2 slightly delayed signals on the same frequency. as you said I got what you called pixelation, bad, when I put the arial in the possiotions where the analogue signal ( we still have it in my area) got ghosting. and where I dont get ghosting the signels not good (sods law).

Things like hair dryers are supposed to be fitted with suppresion capacitors or filters, they dont always work, and I dont know what the guy down stairs switches on when he gets in but it always glitches the DTV.

I think the thing with the mobil phones is due to my wide band ariel setup, and the proximity, the signals are saturating the amplifyers so that they are no longer operating correctly, hence the idea of fitting a TV frequency bandpass filter, before the amplifers. (I need to do research before I buy on this)

I do agree with your friend the about reflection making reception possible, but when it comes to digital, its like crash detection on an ethernet, two signels on the same frequency, it the main signel has sufficient strenth then they can decriminate, if not then, the weaker signel can interfer with the main signel and introduce droped packets.

Also as the poster "Nick" said

"The digital switchover will help considerably - digital signals are currently attenuated to prevent interference on analogue broadcasts. Once the analogue broadcasts are switched off, digital muxes will be broadcast at much higher power. Sadly, since we have to wait until September 2011 for the Emley Moor transmitter to stop broadcasting"

By which time I will have spent my money, to solve the problem.
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