DVB-T with H.264 (MPEG-4)
Please get your coffee cup before you start reading this blog entry, cause this is a longer one…
I haven’t been playing with DVB-T for a while, and when Marcus Overhagen open-sourced his DVB-T work to the Haiku-OS project, I wanted to see how the test broadcasts where coming along in Norway. I knew that Norway was not to use MPEG-2, but instead go for H.264 (MPEG-4). It turned out that NTV already had switched their test broadcasts from the Tryvann antenna to the new and better codec some time end of March.
More or less at the same time Golem.de published:
Nachzügler: Norwegen bekommt das bessere DVB-T
Mit MPEG-4 AVC und aacPlus zum terrestrischen Digitalfernsehen
Yes, Norway was to get better DVB-T then Germany. Well, a better technical solution. Norway already had better DVB-T when NTV did test broadcasts with MPEG-2. NRK often got broadcasted with 9 Mbps while German channels typically got broadcasted 2,5-3 Mbps. This basically ment that the pictures from NRK were of a much higher quality, the German channels looked like a movie from a well-used VHS cassette. The reason for this is simply the available bandwidth, and that German suppliers chose to push more channels to consumers. If Norway had gone for MPEG-2 we would probably had done the same mistake. In short, Norway chose to implement a digital terrestrical HD (High Definition) TV and Germany a SD (Standard Definition) TV, something that will make a significant difference now that more and more people get their HD-Ready flat-panel TVs! The test broadcasts are still only SDTV, but NTV/RiksTV will hopefully move fast on to providing a few channels in HDTV (720p/1080i).
It’s all German software
The Golem article links to a Nürnberg-based company Coding Technologies. The company specialises in audio codecs for mobile, digital bradcasting and Internet, and seems to be the company that is to deliver the audio codec that NTV has chosen to implement, aacPlus. My first thought was: “Not again, yet another audio codec. Why couldn’t they just go for MPEGSurround?”. But having read about the codec and listened to some of the many radio stations (with the latest VLC/Winamp) that already broadcast in this format, I am convinced that NTV did the right decission. The aacPlus (HE-AAC, High Efficiency Advanced Audio Coding) codec is fully standardized in MPEG-4 and capable of delivering stereo CD quality at 48 Kbps and 5.1 surround sound at 128 Kbps. Also 7.1 is possible. As HE-AAC is supported in the open source FAAD/FAAD2 decoding library, my hope is that Haiku-OS can get it implemented fairly soon.
RiksTV will still only have test sendings till some time in September this year, and only the govermental TV channels NRK1 and NRK2 are freely available. You already need a subscription card (not publicly available) to receive broadcasts from TV2 and TVN (TV Norge). To test the solution you need to get hold of the H.264 codec. There are many commercial codecs available, and sadly most of them cost far to much! Luckily I already have H.264, as I have bought the latest version of CyberLink PowerDVD Ultra Ed (for HD DVD). Here is why you should consider buying exactly CyberLink’s codec, for a US $ 100 you get both the codec, a DVD, HD DVD and Blueray playback software. I don’t know of any better deal!
I then bought DVBViewer (for 15€), a really impressive TV software made by Bernd Hackbart. Worth every cent (penny) I paid! The viewer is one of the few solutions that allows you to experience Digital TV on your PC. I have for instance not been capable of watching DVB-T with H.264 directly from Windows Media Center in Vista. Nor have I been able to use Hauppauge’s own viewer.
Elgato EyeTV Hybrid
When it comes to hardware, I have managed to receive the NRK broadcasts with the USB adapter Elgato eyetv hybrid, which actually is nothing else then a Hauppauge WinTV HVR-900, so drivers are available for both Windows XP and Vista. I chose Elgato simply cause my main home machine is a Macbook Pro. Sadly, I haven’t got around to try receiving H.264 broadcasts on my Mac with eyetv.
The first machine I tested was a Lenovo T60 (Intel Core 2 Duo 2500 running at 2 GHz, 2 GB RAM, 64 MB ATI Mobility Radeon X1300, 1400×1050 TFT) laptop running Vista Ultimate Edition. My experience was rather horrible, DVBViewer would be crashing as soon as you started another application or switched to another application to do some work. It would also just die after a few minutes even if it was the only application running. I still haven’t got a clue about what is causing it, Vista, Cyberlink’s H.264 codec, the Hauppauge driver or the DVBViewer?
Dell OptiPlex 745
I was quite disappointed, so I moved over to my work machine, a Dell OptiPlex 745 (Intel Core 2 Duo E6400 running at 2.13GHz, 1066MHz FSB with 2MB L2 cache, 2 GB RAM, ATI Radeon X1300 Pro PCIe 256MB, DVI) still running Windows XP. And WOW, rock solid, DVBViewer hasn’t died on me once!
It is quite fun and interesting to see how much the data transfer has gone down, without the picture quality becoming worse! When NTV was broadcasting in MPEG-2, the data transfer was changing constantly, but often up to 9 Mbps. The “new” test broadcast of NRK in MPEG-4 only has a data transfer of 3,1 Mbps. Sadly the broadcast was only in 4:3 and not 16:9. Another problem that all early birds are having, is that none of us are getting any sound. DVBViewer isn’t capable of making use of the aacPlus codec, as it doesn’t find it. I haven’t found a way to show the viewer where the codec is installed. I have both Winamp and VLC installed, so the codec is there. Don’t get me wrong, I don’t think that DVBViewer is the problem, but I hope that the developer will manage to find a workaround for us. I can hardly wait to try the codec, as the “old” MPEG-1 was streaming with 256 Kbps and wasn’t bad at all! The new codec is streaming at the “impressive” 192 kbps.
With the “new” test broadcasts EPG (Electronic Program Guide) has also been implemented, so with DVBViewer you can read about the upcoming TV shows/programs and schedule your computer as a PVR.
I am looking forward to the day when I finally can show my cable company the finger and move on. I guess many others will do the same! But it all depends on the effort RiksTV is putting down in getting the best channels in their package of about 18-20 channels. Having 50 channels today, and only watching 6-7 of them on a regular basis says a lot!
A few things in the end
I have a few questions that I would like to get answers on, even if I need to find the answers myself:
Has somebody successfully been able to use the H.264 codec from the FFMPEG project?
Has somebody successfully received the test broadcasts with a Mac or in Linux?
Is somebody translating DVBViewer to Norwegian bokmål?
Don’t run out and buy yourself a DVB-T card/adapter for your computer. Most likely many of these cards will not be working satisfyingly in the Norwegian DTT network, as they are not manufactured after the specifications of the Norwegian DTT network. NTV/RiksTV are in the process of establishing test and certification of receivers to make it easier for consumers to choose what to buy.