TMPGE settings for TV broadcast

[williamb]

Hi
Instead of dumping my TVC onto DigiBeta, I can convert it to an Mpeg2 and upload it to www.dubsat.co.nz who then send it to the stations for me…There are several choices I have and I was hoping for some feed back.

PAL format
I set the Video to ‘CQ’ and set both max and minimum to 8000k/bits sec.
Slider obviously at 100%
Profile and level I’m not sure about…I set it to high profile but there 3 to choose from.
Motion search is set to High Quality (very slow)

I don’t convert the Audio because they accept WAV anyway.

What I don’t understand is the Choices under GOP tab…what can I do to increase quality here?
I don’t understand Quantize matrix Tab…and again…what is best max quality for TVC.

Really appreciate some understanding here and by the way…I can put that Mpeg file on the timeline if the VT4.6…I notice its looking…mmm….like there is a field issue…its not nice and smooth like the original RTV.

Needing to get this done by tonight so feed back would be awesome.

[robewil]

http://dvd-hq.info/Compression.html
There is a lot of very useful information here.

[rbartlett]

It is hard to know whether this is for use by a video server that plays-out or whether you need it to meet the ingest requirements of such a video server. Invariably these units can repackage existing encodings (e.g. from program stream out to STDI transport stream) or even re-encode on the fly (from a higher bitrate, higher subsampling mode etc) and also incorporate any metadata that you may wish to have conveyed (program info, subtitles/captions, secondary streams, etc).

However it seems likely that for a PAL DVB transmission, that you'd be somewhere within these boundaries:

2-6Mbps VIDEO MPEG-2 720x576 Main Profile at Main Level, interlace, upper frame first, 50 fields per second
4:2:0 subsampling
PCM audio 16bit 48kHz 2+ channels.
Packaged in a transport stream with nothing in particular (00) stated for the PID (program ID)

If you are heading towards a broadcast spec worth singing about:
9-15Mbps 720x576 MP @ ML, interlace, UFF, 50 fields per sec
4:2:2
00 PID.

Motion search functions in TMPGEnc and pre-filtering ought to be an encoder feature only. That shouldn't cause any incompatibility downstream as long as you are happy with the look. The beauty of MPEG being that the decoder complexity remains the same, the hard work is done at the encoding stage.

They'd probably accept a program stream or system stream. I forget the exact term for the packaging of MPEG and whether one or the other isn't possible beyond MPEG-1.


Given that they accept WAV, I'd be surprised if they didn't accept DV.AVI or DV.MOV. Which being intraframe would be better than MPEG-2 in all ways other than the subsampling limitations.

Can't help but think that DubSat ought to give you guidance on this.
Did you fathom 8Mbps from anywhere, or were you thinking of the typical max rates for the MPEG-2 video stream part of DVD-Video?
PCM 24bit 96kHz 2+ channels.

I've no first hand experience. I also figured that these tasks were done by appliances more often than not. So SDTI and SD-DVB info ought to be perused. Also DBS and CATV guidance ought to be at least googled before you commit to anything hard and fast.

Any more takers?

[williamb]

help...says that High Profile is best for Video?

[rbartlett]

Main Profile at Main Level is generally regarded as essential for final delivery into a standard def market. Higher than that on either side of the equation - and you'll probably need a different bitrate to honour it.

If you want to move up a gear, anticipate that your D1 sources will be squished less, but that you'll need a bitrate of maybe 40 or 80Mbps. I doubt the space segment will carry that economically, but YMMV.

Again to save wasting time, I'd ask their support folks what conforms. You may have to pay quite a lot of attention to meeting their specific legal levels requirements for AV. It isn't always a good assumption to make that your previous work got accepted so that this would too. Perhaps this isn't an issue, but as you have brought up the subject of MPEG-2 compression, I'm figuring that there is a gap to be filled maybe more than just the one gap...?

http://en.wikipedia.org/wiki/MPEG-2#Profiles_and_Levels

This extract probably won't look that great after pasting:

MPEG-2 Profiles Abbr. Name Frames YUV Streams Comment
SP Simple Profile P, I 4:2:0 1 no interlacing
MP Main Profile P, I, B 4:2:0 1
422P 4:2:2 Profile P, I, B 4:2:2 1
SNR SNR Profile P, I, B 4:2:0 1-2 SNR: Signal to Noise Ratio
SP Spatial Profile P, I, B 4:2:0 1-3 low, normal and high quality decoding
HP High Profile P, I, B 4:2:2 1-3
MPEG-2 Levels Abbr. Name Pixel/line Lines Framerate (Hz) Bitrate (Mbit/s)
LL Low Level 352 288 30 4
ML Main Level 720 576 30 15
H-14 High 1440 1440 1152 30 60
HL High Level 1920 1152 30 80
Profile @ Level Resolution (px) Framerate max. (Hz) Sampling Bitrate (Mbit/s) Example Application
SP@LL 176 × 144 15 4:2:0 0.096 Wireless handsets
SP@ML 352 × 288 15 4:2:0 0.384 PDAs
320 × 240 24
MP@LL 352 × 288 30 4:2:0 4 Set-top boxes (STB)
MP@ML 720 × 480 30 4:2:0 15 (DVD: 9.8) DVD, SD-DVB
720 × 576 25
MP@H-14 1440 × 1080 30 4:2:0 60 (HDV: 25) HDV
1280 × 720 30
MP@HL 1920 × 1080 30 4:2:0 80 ATSC 1080i, 720p60, HD-DVB (HDTV)
1280 × 720 60
422P@LL 4:2:2
422P@ML 720 × 480 30 4:2:2 50 Sony IMX using I-frame only, Broadcast "contribution" video (I&P only)
720 × 576 25
422P@H-14 1440 × 1080 30 4:2:2 80 Potential future MPEG-2-based HD products from Sony and Panasonic
1280 × 720 60
422P@HL 1920 × 1080 30 4:2:2 300 Potential future MPEG-2-based HD products from Panasonic
1280 × 720 60

[rbartlett]

Frame 48 of this powerpoint:
http://www.iee.org/oncomms/pn/visualinformation/Tutorial%20001%20Nilsson.ppt
suggests that you might be right in that DVB systems do have a tolerance for accepting 4:2:2@ML or HighProfile@MainLevel MPEG-2.

I've not fathomed the typical GOP structure (assuming closed), or whether CBR is necessary. The vendors sell a lot of $60,000 equipment based on hiding the real specifications of what can be carouseled, served, delivered and decoded.

20,40,50(IMX), 80 and 100Mbps MPEG-2 seem to hit distribution/library carousels. kbps through to 50+Mbps seem valid for DBS for station-to-station feeds. A lot less for final distribution, perhaps down to 1.5Mbps through to just under 20Mbps. Typ. 9.8Mbps or 15Mbps depending on how premium the TV programme channel is.

DVB Wrappers, IMX, NGIS, DAVIC, DOCSIS all make good google searches, but nothing that useful came of my quest.

[williamb]

I appreciate your technical information
Some good links there…although I was getting cross-eyed reading some of it.

Here is some information I received from dubsat…

Problem is…are recommendations based on high quality…or based on reducing file size…whilst both are opposite…both a positive depending on your application…I of course are only interested in quality…and if I could, would supply Uncompressed and would be happy to travel 30-min to do so…file size is not my concern…

Its says “longer GOP” is best…do you or anyone know what settings in TMPGE I would use…and will that increase the quality or just compress it more?

From dubsat…
“DubSat requires an MPEG2 rendering of the spot. This is can be a single file Program Stream file containing the combined (multiplexed) Video and Audio, or two separate Video and Audio files.

If you choose to send separate files, the Video should be an MPEG2 Elementary Stream, and the Audio either a WAV or AIFF file.

The MPEG2 file should adhere to the Australian TV standard of 720x576. The ‘DVD’ output option for most MPEG encoders will produce this.

The choice of MPEG bitrate is left to the clients’ discretion. The bitrate should be high enough that there are no objectionable visual artifacts, but small enough that the file is an acceptable size to handle.

Current experience indicates that encoding at the high end of the capabilities of a DVD – 8 Mbit or above - provides good results. Try to use a setting with a longer GOP so as to get maximum benefit from the MPEG process.

Note that the 720x576 requirement is the same as that of the Video recorded on Digital Betacam/DVC Pro, and typical Edit Systems. It is also the native resolution of the TV station transmission path. MPEG material supplied at that resolution would reach the viewers’ home via a settop box with absolutely no alteration in the resolution or color fidelity:

[rbartlett]

How about making it like this?

SDTI and IMX both have their foundations in the Betacam SX format.
4:2:2Profile@MainLevel is HP@ML.

Betacam SX (Mpeg 4:2:2P@ML IBIB 2 frame GOP system, 18.7 Mbits/sec video bitrate)

Upper frame first.

Select CBR (VBR would be optional, maybe min 4Mbps, average 8Mbps, peak 15 or 18.7Mbps)
Needs aspect ratio set correctly.
(2-pass is your own choice if , really for VBR)
Closed GOP is your choice.
DC co-efficients - optionally 10bit.
Elementary stream - should be selectable, saves all that artificial header stuffing into a pseudo transport stream.
Separate WAV is your own choice.

This ought to look good with a IBIBIB GOP. Although at 18Mbps, you might be tempted to go I-Frame only. Try both. If you have a lot of cross fades, regular I-Frames can be fine and more consistent with a high bitrate.

This leaves you with sequence header options; Non-linear quantization; Table 1 optimization, alternate pattern scan; motion compensation (fielded mode); pre-filtering; Primaries/transfer/matrix-coefficient references, VBV buffer sizes.

Betacam SX is probably described well. I couldn't find a TMPGEnc project setting for you. Although that doesn't mean that one doesn't already exist.

[williamb]

OK
I have rendered a 15TVC in the following all in default Quantize Matrix:

10bit MP@HL standard GOP…
10bit MP@HL i only GOP…
10bit MP@HL ip GOP…
10bit MP@HL i x1000 GOP…(thought for a laugh)
10bit 422P@ML
11bit HPHL 1440
11bit HPHL I only GOP…
11bit HPHL Standard GOP…

Put them all on the VT timeline and closely examined them all…

Using the standard GOP gave me the best picture…anything else had pixelization around smaller text in the video.

So setting GOP to Standard and default Quantize Matrix…I could not tell visually the difference.
All High Profile were the same file size at 13,633 KB
10bit MPHL was 13,593

they all seem to play the same…this of course if from the timeline VT4.6…

So I guess if your transmitting your TVC and you need to MPEG then one of the 11bit is the best (maybe not for DVD)
Other settings I used…

CB (Constant Bitrate) min 8000kp max 8000kp
Motion search HQ (very slow)

[williamb]

WAIT…While writing this I see that if I select HP I can increase the CB rate…tried it at 20,000kb seems to work fine...cool...

[ScorpioProd]

Ah, but in reading what you posted that the broadcaster wants, they specifically mentioned on a DVD, didn't they?

Well, if you want it to playback on a DVD, it needs to be within DVD specs.

Are you planning to deliver it on a DVD? If so, 8Mb/s is the best quality you can use. And you need to stick with DVD specs for the rest.

Again, from everything you posted that THEY said, they seem to want a standard DVD.

Or are you looking to deliver it on something other than a DVD? If so, how are they gonna play it?

[rbartlett]

It might be put on a DVD-ROM along the way, not for playback directly. Williamb is though primarily compressing the project into an MPEG-2-ES.mpg. He wants to do this lightly enough to allow it to be accepted by the transfer house. Who will in turn send it out via a satellite feed. Then I take it that the playout/stations will recompress for DVB-S or DVB-T within the constraints of that system. So it pays to have this as lightly compressed with the best colour space as can be mustered with MPG-2. They've suggested MPEG-2 DVD profile parameters as they say that the quality is ample. Depending on the programme length the chances are that the sat-distributor and the stations will not even know they've got better quality coming into them. It ought to be a venture for piece of mind.

However, when pushed, a 422@MainLevel MPEG-2 long GOP DVD profile file maybe all that is accepted. Just that Williamb hasn't been told what the maximums are. I don't believe that lossless-math or lossless-virtually is an option for MPEG-2 and the file sizes will start to approach the 70GB per hour level.

From what I understand of these goings on, possibly via promotion of IMX media types and SDTI industry hoses, the use of 10,20,30,40,50 and 80Mbps MPEG-2 422@MainLevel CBR seems to be or have been a popular transfer format. I guess this would be more for DLTs passing about the place more so than private station satellite feeds,.....

Betacam SX constrained parameters on TMPGEnc seems like a good move what with NO other direction from Dubsat. 20Mbps is just a small step on from the 18Mbps (poss. NTSC version) standard that I've been reading about.
I'd be more impressed if Dubsat put this information out publicly on their website. Perhaps they do if you login.

If time permits, running an 8Mbps version in 422@ML maybe worthwhile too. It'll take less than half the time to transfer and either type might suffer similarly when recompression occurs at the point of playout/broadcast. However Betacam SX was designed to serve news gathering and at that time this would have then gone out uncompressed via D1 analogue broadcasting. Times change but the good intentions of the engineering elements of the programme makers needn't go down the food chain too far.

[williamb]

I was putting a the file on a DVD Data disk...not provide an actual DVD

How do i make it 20Mbs is that through the settings by Constant Quality? and if so what number do you recommend....i assume 20,000kps?

by the way they are only one 15 and one 30-second adverts

[williamb]

by the way...for the last 96-hours i've had maybe 10 hours sleep...tryng to get this TVC made...Client want big change so i will be up all night again...
Got two computers rendering differnet scenes and one scene should take about an hour...so on the floor for a quick nap!

[ScorpioProd]

OK... Only thing is, I think you might need something other than TMPGEnc to do the encoding if you want to go beyond DVD specs...

TMPGEnc, though it does include different profiles and levels, is really made for DVD Video encoding...

And as such, I don't think you will be able to push the data rate over 8Mb/s.

I just tried and I don't see a way to do that. In fact, having used the program for many years, I do remember being able to set it higher in earlier versions long ago, and then it was restricted to 8Mb/s because too many people didn't understand the specs and were making non-complient MPEG-2 files for DVD.

[williamb]

Went into a DUBSAT rep today to process my tvc...it seems the 10bit Main Profile is perfectly fine...
We tried loading the high profile 11bit 20k format and whilst it worked they had some equipment problems...they initially thought it was the file so used the 10bit one...
But both were fine...it was equipment failure.

Cheers
for all your input

[williamb]

So what about setting it to CB and increasing the bitrate (found in CQ setting) to something like 20,000?

[ScorpioProd]

So you're saying TMPGEnc lets you set that high a data rate? Which version of TMPGEnc are you running?

[williamb]

2.5 bought it a few days ago