Can all PC-based tuners receive H.264 broadcasts?

[DJ_Borat]

I'm thinking of getting an HDTV tuner (I'm looking at the AVerMedia AVerTV Combo PCI-E).

I read on Wikipedia that many HDTVs can only receive MPEG-2 HDTV. I'm guessing that this is because HDTVs use a fixed-function DSP to decode the video stream. My question is: Can all PC HDTV tuner cards receive H.264 broadcasts, since they rely on the PC's multi-function CPU to handle the decoding?

Thanks.

[neuron2]

Some of the cards still use on-board decoders, so the answer is no. Even for the ones that decode on the PC, you'd have to ensure that the associated software can handle H.264. Not all of them do.

[LoRd_MuldeR]

For H.264-encoded HD content you need a DVB-S2 card. With an older DVB-S card you can only receive MPEG-2 broadcast, SD as well as HD.

It seems some channels were broadcasting MPEG-2 HD in that past, but they've all switched over to H.264 (DVB-S2) now. I guess they want to save some bandwidth.
With my DVB-S card, I currently cannot see any HD channels. Except for one, which shows a "test pattern" and the info that the next broadcast will be on xmas.

[Inventive Software]

DVB-T2 (H.264/AVC over terrestrial) is currently being tested, and is due for deployment in the next year or so, so that's another factor to consider.

@Lord_Mulder: Is your satellite dish pointed to the right satellite?

[LoRd_MuldeR]

@Lord_Mulder: Is your satellite dish pointed to the right satellite?

I hope so :D

Currently I get all the SD channels, that I'm supposed to get at my location.
HD doesn't work, because my DVB-S1 card doesn't support H.264 and there are no MPEG-2 HD channels any more.
Or are you aware of any that I can receive in Central Europe?

[Inventive Software]

There's a few on Astra 28.2E, there are some on Hotbird, and if memory serves, there are some on another Astra satellite, but I can't remember the number.

Otherwise, upgrade yer card! :D

[LoRd_MuldeR]

There's a few on Astra 28.2E, there are some on Hotbird, and if memory serves, there are some on another Astra satellite, but I can't remember the number.

Otherwise, upgrade yer card! :D

I just bought that card, after my old one had been grilled by a short-circuit in our satellite-switch :rolleyes:

A ran a full search recently. So please name me a few HD channels that are actually sending in MPEG-2 :p

(For example ARTE HD uses "Modulation: DVB-S2" according to their homepage, Pro7/Sat.1 stopped HD broadcast a while ago.
ARD/ZDF won't start HD broadcast until 2009 and I'm pretty sure they'll use H.264/DVB-S2 too)

[Inventive Software]

I am unaware of any broadcasting in MPEG-2. But a quick Google search brought up this site: http://www.lyngsat.com/hd/28east.html, which is fantastic for channel listings; this one is for 28.2E and Astra/associated satellites. What satellite is your dish pointed to, out of curiosity? In Germany, you might have trouble receiving signals from 28.2E, so this list: http://www.lyngsat.com/hd/index.html, might be your best point.

Everything HD is moving to DVB-S2 unfortunately, so an upgrade might be in order. But DVB-S2 is backwards-compatible with DVB-S, so you're set for both SD and HD with a new DVB-S2 card.

[LoRd_MuldeR]

I will consider upgrading to DVB-S2 when there are more German HD channels available and when there is more "true" HD content, not upscaled SD stuff.

And I think we are pointing to the "Astra 1F/1G/1H/1KR/1L" satellites...

[reepa]

DVB-T2 (H.264/AVC over terrestrial)

H.264 works over DVB-T too. Norway and Estonia use it for example.

[paulvdb]

H264 doesn't have to use DVB-S2 but most H264 channels use it because DVB-S2 allows more bandwidth per transponder and H264 and DVB-S2 were introduced around the same time so all stand-alone H264-capable satellite receivers can also tune DVB-S2. But some H264 channels broadcast on DVB-S like BBC HD for example.

[LoRd_MuldeR]

H264 doesn't have to use DVB-S2 but most H264 channels use it because DVB-S2 allows more bandwidth per transponder and H264 and DVB-S2 were introduced around the same time so all stand-alone H264-capable satellite receivers can also tune DVB-S2. But some H264 channels broadcast on DVB-S like BBC HD for example.

BBC HD doesn't work for me. I only get black screen. But DVBViewer seems to load the CoreAVC decoder though :rolleyes:

However "EinsExtra HD" is working with HD and H.264 over DVB-S1. It cureently shows a "test screen" announcing the next broadcast for xmas...

[lucassp]

H.264 works over DVB-T too. Norway and Estonia use it for example.

Romania too :) Of course, only experimental in one city.

[LoRd_MuldeR]

How is the quality of H.264-compressed HD content over DVB-T with it's limited bandwidth ???

On the one hand H.264 compresses more efficient than MPEG-2. On the other hand the number of pixel increases drastically from SD to HD.
The last time I used DVB-T (SD, MPEG-2) I saw a lot of blocking. Much more blocking than I see in DVB-S broadcast...

[Inventive Software]

DVB-T's not limited by bandwidth, as such, but the receiver is dependant on a very good signal SNR and quality. What you saw was probably a low-bitrate channel or a weaker-than-the-norm signal.

[LoRd_MuldeR]

No, this isn't some "low bitrate" channel. It's German public broadcasting...

Well, the stream I captured from DVB-T has a maximum bitrate of 5400 KBit/s and an average bitrate of 3830 KBit/s.
A capture from the very same channel over DVB-S1 has got a maximum bitrate of 8000 KBit/s and an average bitrate of 5040 KBit/s.
That's a significant difference!

Also many channels compress their sources for DVB-S first. Later the DVB-S stream will be re-encoded for DVB-T.


[EDIT]

My observations matches the info from Wikipedia:
Die meisten Hauptsender (ARD, ZDF, ORF) senden heute per DVB-S mit MPEG2 Datenraten von 7–8 MBit/s (verglichen mit DVB-T mit 3–5 MBit/s).

In English:
Most main channels (ARD, ZDF, ORF) transmit MPEG-2 data over DVB-S at data rates of 7-8 MBit/s nowadays (compare to DVB-T with 3–5 MBit/s).

[burfadel]

1920x1080 HD in Mpeg-2 works fine over DVB-T. You can have a HD channel with that resolution (and AC3 audio) and a couple of SD channels with the bandwidth available for each channel. h.264 may be slightly more susceptible to interference (as an assumption), since its more efficient encoding any stream errors that occur will be carried through easier. A demuxer and stream 'cleaner' would have to be used to make it usable, such as ProjectX, however that doesn't support h.264, at least yet... The only time that blockiness can be seen is at the very end of fades, and thats only noticeable on the computer screen with a frame-by-frame look.

I'm not sure what the I-frame interval for DVB-T is, I assume 1 second? (it has to be low to allow quick channel switching, and the non-propagation of stream errors). The efficiency between h.264 and mpeg-2 with that small of an interval would most likely be less than what you use on a personal computer. There's no doubt it would still be substantial! The main problem with adaption of these standards is their expected usefulness period. It is unreasonable to expect people to continue updating their hardware each time a new format is used, its not as simple as updating FFDshow etc! let alone the broadcasters adoption of the standards. I would presume those countries that already have MPEG-2 adopted (almost 9 years since DVB-T began broadcasting in Australia for example) as the DVB-T standard would persist with the current format at least for a while. h.265 might be used in the future, once it is finalised (hopefully a lot of the work on x264 can be carried through to this) - although I have heard somewhere h.265 will just be a superset of h.264, then its possible that a move to a wavelet based codec in the distant future will be done if the Super HD format takes off (tested in Japan, it is at least 4x the resolution of HDTV).

To answer your question, I'm pretty sure you need a h.264 specific capable card to view h.264.

[LoRd_MuldeR]

To answer your question, I'm pretty sure you need a h.264 specific capable card to view h.264.

Nope! There is no "h.264 capable card". There are DVB-S1, DVB-S2, DVB-T1 or DVB-T2 capable cards.

The DVB-S and DVB-T standards, including the "2.0" versions, only define the physical transmission of the signal.
But they do not define the video compression/decompression that has to be used!
What video format can be decoded (or not decoded) depends on the player software and the decoders it uses.

H.264 can be transferred over DVB-S1 just fine, but they usually don't do it. That's because standalone DVB-S1 devices are limited to MPEG-2.
What is the sense in transferring some format over DVB-S1 that no DVB-S1 receiver is able to decode? It would only be useable by PC users!
And since you need new standalone devices for H.264 support anyway, they switch from DVB-S1 to DVB-S2 at the same time.

So in reality you either have "MPEG-2 over DVB-S1" or "H.264 over DVB-S2". But that's not a technical prerequisite, but a marketing decision!
Also HD content could be transmitted via MPEG-2 + DVB-S1 just fine, but it eats too much bandwidth and hence it's too expensive.
DVB-S2 offers more bandwidth from the beginning and H.264 compresses more efficient. So they use H.264 + DVB-S2 for HD content now.

As said before: I can receive a "HD Test Channel" that is sending H.264 data using my "old" DVB-S1 card and DVBViewer+CoreAVC just fine ;)
But that's really the only HD channel I can receive. All the others are on DVB-S2 now...

[lucassp]

How is the quality of H.264-compressed HD content over DVB-T with it's limited bandwidth ???


Here's a small sample a I found on a local forum: http://www.dump.ro/download.php?id=31791&act=rbqhNNlsJgD69zfU

[LoRd_MuldeR]

Here's a small sample a I found on a local forum: http://www.dump.ro/download.php?id=31791&act=rbqhNNlsJgD69zfU

Not that bad, really :cool: