Seven's HD 576p

[Ext User(bill)]

I'm a bit confused as to how Seven broadcast HD movies.

As far as I know, please correct me if I'm wrong, 576i is 50 interlaced
fields per second represented by 25 digital frames/sec where as 576p is
50 progressive frames per second represented simply by 50 frames/sec.

What then doesn't make sense is how Seven can broadcast HD movies which
are originally shot at 24fps and simply sped up to 25fps for PAL and say
that the content is HD when there's only 25fps fitting into same
resolution as SD just at twice the frame rate.

Am I hopelessly wrong in my understanding of 576p or is Seven's HD a
waste of bandwidth operating at the same resolution just with 50fps
which ends up being a waste anyway on films originally shot in 24fps anyway?

Thanks,

bill

[Ext User(David Z)]

"bill" <user@example.net> wrote in message
news:dnrmul$220o$1@otis.netspace.net.au...
> I'm a bit confused as to how Seven broadcast HD movies.
>
> As far as I know, please correct me if I'm wrong, 576i is 50 interlaced
> fields per second represented by 25 digital frames/sec where as 576p is 50
> progressive frames per second represented simply by 50 frames/sec.

You're confused. All Australian TV is 25 frames/sec. 576i still has 25
frames, except each frame is displayed twice, with half the picture
information contained in each 'field' (a total of 50 fields). 576p on the
other hand is 25 frames/sec, with each frame containing the full picture
information. It is not 50 frames/sec as you state.

[Ext User(Ozdude)]

"David Z" <dave@hotmail.com> wrote in message
news:DFeof.6974$V7.6339@news-server.bigpond.net.au...

> You're confused. All Australian TV is 25 frames/sec. 576i still has 25
> frames, except each frame is displayed twice, with half the picture
> information contained in each 'field' (a total of 50 fields). 576p on the
> other hand is 25 frames/sec, with each frame containing the full picture
> information. It is not 50 frames/sec as you state.

Hi David,

I have a feeling $even aren't that informed either ;)

I watch 7HD demo loop all day at work on the screens there (CRT, LCD,
Plasma) and some scenes there is a definite interlace flicker. I have come
to conclusion that they shoot on the same old interlace cameras, then the
downstream starts to play with the fields until it reaches the muxer,which
at the last minute progresses it.

If this is viewed on a CRT without progressive scan, it's then reinterlaced
by the STB and receiver, and an almighty visual mess is created.

It's not pretty and I say it's not HD at all - just "progressive-ized SD",
and not done well at that.

Oz

[Ext User(bill)]

Ozdude wrote:
> "David Z" <dave@hotmail.com> wrote in message
> news:DFeof.6974$V7.6339@news-server.bigpond.net.au...
>
>
>>You're confused. All Australian TV is 25 frames/sec. 576i still has 25
>>frames, except each frame is displayed twice, with half the picture
>>information contained in each 'field' (a total of 50 fields). 576p on the
>>other hand is 25 frames/sec, with each frame containing the full picture
>>information. It is not 50 frames/sec as you state.
>
>
> Hi David,
>
> I have a feeling $even aren't that informed either ;)
>
> I watch 7HD demo loop all day at work on the screens there (CRT, LCD,
> Plasma) and some scenes there is a definite interlace flicker. I have come
> to conclusion that they shoot on the same old interlace cameras, then the
> downstream starts to play with the fields until it reaches the muxer,which
> at the last minute progresses it.
>
> If this is viewed on a CRT without progressive scan, it's then reinterlaced
> by the STB and receiver, and an almighty visual mess is created.
>
> It's not pretty and I say it's not HD at all - just "progressive-ized SD",
> and not done well at that.
>
> Oz
>
>


I'm confused as to what the difference is when storing digital Video
Interlaced or Progressive? How is it encoded differently.

I always thought 576i was simply 25fps with every odd and even line
representing the 2 fields stored within the frame and the same encoding
can be used for 576p except it's all just 1 frame stored in each frame
instead of 2 fields.

so 576p is 25 frames per second? 576i is also 25fps but with 2 fields in
each frame representing 50fields/sec?

[Ext User(tonymy01)]

"David Z" <dave@hotmail.com> wrote in message
news:DFeof.6974$V7.6339@news-server.bigpond.net.au
> "bill" <user@example.net> wrote in message
> news:dnrmul$220o$1@otis.netspace.net.au...
>> I'm a bit confused as to how Seven broadcast HD movies.
>>
>> As far as I know, please correct me if I'm wrong, 576i is 50
>> interlaced fields per second represented by 25 digital frames/sec
>> where as 576p is 50 progressive frames per second represented simply
>> by 50 frames/sec.
>
> You're confused. All Australian TV is 25 frames/sec. 576i still has
> 25 frames, except each frame is displayed twice, with half the picture
> information contained in each 'field' (a total of 50 fields). 576p
> on the other hand is 25 frames/sec, with each frame containing the
> full picture information. It is not 50 frames/sec as you state.

He isn't confused, for 7,ABC and SBS to allow 576p to be called "high
definition" it is actually 50frames/sec. They simply double every frame up
to achieve this, you can see this if you capture a bit of these channels and
then step through frame by frame and see that each frame repeats once.
(What would be really really cool is if they sourced 50frames/sec
progressive cameras, then sport like golf, tennis etc would look awesome!).

Regards

--�
Tonymy01
http://tonyspage.abock.de for Topfield TAPS, links etc.

[Ext User(tonymy01)]

"bill" <user@example.net> wrote in message
news:dnt8ui$2l4u$1@otis.netspace.net.au
> I'm confused as to what the difference is when storing digital Video
> Interlaced or Progressive? How is it encoded differently.

Movies are "progressive" in nature, in that 2 fields are created from a
"still" film frame. So while it is stored interlaced, simply weaving will
result in progressive with no artifacts. Displaying each field on an
interlaced TV also looks fine.

Video on the other hand has 50 unique fields per second, and weaving will
result in that "combing" style artifacting as each field is from a unique
moment in time. This recording looks fine on an interlaced TV, but weving
won't look good, so normally bob is used where each line is doubled up to
make 288lines 576. Typically a plasma/whatever will detect film or video
and use the different de-interlacing technique depending on its detection
scheme.

576p (for digital DTV transmission) is 50frames/sec and they achieve this by
doubling each frame, as I specified in my other post.

Regards

--�
Tonymy01
http://tonyspage.abock.de for Topfield TAPS, links etc.

[Ext User(Mike)]

David Z wrote:

>>As far as I know, please correct me if I'm wrong, 576i is 50 interlaced
>>fields per second represented by 25 digital frames/sec where as 576p is 50
>>progressive frames per second represented simply by 50 frames/sec.
>
>
> You're confused. All Australian TV is 25 frames/sec. 576i still has 25
> frames, except each frame is displayed twice, with half the picture

Actually, you are both right sometimes.
Interlaced TV is 50 fields/second. If shot on film, it is as David days,
with 25 frames split into 50 fields.
But on video, its better than that. Its usually shot 50 "frames" a
second, so the second field is recorded it time in between the fields on
either side. On a CRT display, the human eye will percieve smoother
motion than if it was show on film at 24 (or 25) fps.

On a digital display, a computer must de-interlace. It could in theory
interpolate to 50 fps. (Q) Do many LCD or plasmas do that?
My de-interlacer just generates 25 fps.

> 576p on the other hand is 25 frames/sec, with each frame containing the full picture
> information. It is not 50 frames/sec as you state.

Oh yes it is. Except that most of the time, the source is 25fps, so
576p shows pairs of identical frames. Even the 7 HD demo loop
shows every frame twice. (I single-stepped it on the PC)

here is what I see on 7-HD:

VIDEO MPEG2(pid=1601)AUDIO MPA(pid=1602) NO SUBS (yet)! PROGRAM N. 0
Opened TS demuxer, audio: 50(pid 1602), video: 10000002(pid 1601)...
VIDEO: MPEG2 720x576 (aspect 3) 50.000 fps 9000.0 kbps (1125.0 kbyte/s)

[Ext User(David Z)]

"bill" <user@example.net> wrote in message
news:dnuglm$2lj$1@otis.netspace.net.au...
> Mike wrote:
>> David Z wrote:
>>
>>>> As far as I know, please correct me if I'm wrong, 576i is 50 interlaced
>>>> fields per second represented by 25 digital frames/sec where as 576p is
>>>> 50 progressive frames per second represented simply by 50 frames/sec.
>>>
>>>
>>>
>>> You're confused. All Australian TV is 25 frames/sec. 576i still has 25
>>> frames, except each frame is displayed twice, with half the picture
>>
>>
>> Actually, you are both right sometimes.
>> Interlaced TV is 50 fields/second. If shot on film, it is as David days,
>> with 25 frames split into 50 fields.
>> But on video, its better than that. Its usually shot 50 "frames" a
>> second, so the second field is recorded it time in between the fields on
>> either side. On a CRT display, the human eye will percieve smoother
>> motion than if it was show on film at 24 (or 25) fps.
>>
>> On a digital display, a computer must de-interlace. It could in theory
>> interpolate to 50 fps. (Q) Do many LCD or plasmas do that?
>> My de-interlacer just generates 25 fps.
>>
>>> 576p on the other hand is 25 frames/sec, with each frame containing
>>> the full picture information. It is not 50 frames/sec as you state.
>>
>>
>> Oh yes it is. Except that most of the time, the source is 25fps, so 576p
>> shows pairs of identical frames. Even the 7 HD demo loop
>> shows every frame twice. (I single-stepped it on the PC)
>>
>
> So in the end the perfect format for movies is really 1080i since movies
> have little benefit from being shown in 576p since it is just displaying
> each frame twice.
>
> Where as with 1080i there is an increase in resolution and no wasted
> frames. So why do Seven bother with 576p, I guess it baffles us all..

Actually 720p is better as there is apparantly more 'perceived' resolution.
That is, 720p looks more impressive to most people than 1080i. Its a shame
the format isn't widely used here, and that it won't be used on HD-DVD
either.

[Ext User(bill)]

Mike wrote:
> David Z wrote:
>
>>> As far as I know, please correct me if I'm wrong, 576i is 50
>>> interlaced fields per second represented by 25 digital frames/sec
>>> where as 576p is 50 progressive frames per second represented simply
>>> by 50 frames/sec.
>>
>>
>>
>> You're confused. All Australian TV is 25 frames/sec. 576i still has
>> 25 frames, except each frame is displayed twice, with half the picture
>
>
> Actually, you are both right sometimes.
> Interlaced TV is 50 fields/second. If shot on film, it is as David days,
> with 25 frames split into 50 fields.
> But on video, its better than that. Its usually shot 50 "frames" a
> second, so the second field is recorded it time in between the fields on
> either side. On a CRT display, the human eye will percieve smoother
> motion than if it was show on film at 24 (or 25) fps.
>
> On a digital display, a computer must de-interlace. It could in theory
> interpolate to 50 fps. (Q) Do many LCD or plasmas do that?
> My de-interlacer just generates 25 fps.
>
>> 576p on the other hand is 25 frames/sec, with each frame containing
>> the full picture information. It is not 50 frames/sec as you state.
>
>
> Oh yes it is. Except that most of the time, the source is 25fps, so
> 576p shows pairs of identical frames. Even the 7 HD demo loop
> shows every frame twice. (I single-stepped it on the PC)
>

So in the end the perfect format for movies is really 1080i since movies
have little benefit from being shown in 576p since it is just displaying
each frame twice.

Where as with 1080i there is an increase in resolution and no wasted
frames. So why do Seven bother with 576p, I guess it baffles us all..

[Ext User(bill)]

David Z wrote:
> "bill" <user@example.net> wrote in message
> news:dnuglm$2lj$1@otis.netspace.net.au...
>
>>Mike wrote:
>>
>>>David Z wrote:
>>>
>>>
>>>>>As far as I know, please correct me if I'm wrong, 576i is 50 interlaced
>>>>>fields per second represented by 25 digital frames/sec where as 576p is
>>>>>50 progressive frames per second represented simply by 50 frames/sec.
>>>>
>>>>
>>>>
>>>>You're confused. All Australian TV is 25 frames/sec. 576i still has 25
>>>>frames, except each frame is displayed twice, with half the picture
>>>
>>>
>>>Actually, you are both right sometimes.
>>>Interlaced TV is 50 fields/second. If shot on film, it is as David days,
>>>with 25 frames split into 50 fields.
>>>But on video, its better than that. Its usually shot 50 "frames" a
>>>second, so the second field is recorded it time in between the fields on
>>>either side. On a CRT display, the human eye will percieve smoother
>>>motion than if it was show on film at 24 (or 25) fps.
>>>
>>>On a digital display, a computer must de-interlace. It could in theory
>>>interpolate to 50 fps. (Q) Do many LCD or plasmas do that?
>>>My de-interlacer just generates 25 fps.
>>>
>>>
>>>> 576p on the other hand is 25 frames/sec, with each frame containing
>>>>the full picture information. It is not 50 frames/sec as you state.
>>>
>>>
>>>Oh yes it is. Except that most of the time, the source is 25fps, so 576p
>>>shows pairs of identical frames. Even the 7 HD demo loop
>>>shows every frame twice. (I single-stepped it on the PC)
>>>
>>
>>So in the end the perfect format for movies is really 1080i since movies
>>have little benefit from being shown in 576p since it is just displaying
>>each frame twice.
>>
>>Where as with 1080i there is an increase in resolution and no wasted
>>frames. So why do Seven bother with 576p, I guess it baffles us all..
>
>
> Actually 720p is better as there is apparantly more 'perceived' resolution.
> That is, 720p looks more impressive to most people than 1080i. Its a shame
> the format isn't widely used here, and that it won't be used on HD-DVD
> either.
>
>


However for movies which aren't originally filmed with interlacing
anyway they'd benefit more from the higher resolution than the doubled
frame rate making 1080i more suitable as a movie format.

[Ext User(Bounty Bob)]

tonymy01 wrote:
> "David Z" <dave@hotmail.com> wrote in message
> news:DFeof.6974$V7.6339@news-server.bigpond.net.au

>>"bill" <user@example.net> wrote in message
>>news:dnrmul$220o$1@otis.netspace.net.au...

>>>I'm a bit confused as to how Seven broadcast HD movies.

>>>As far as I know, please correct me if I'm wrong, 576i is 50
>>>interlaced fields per second represented by 25 digital frames/sec
>>>where as 576p is 50 progressive frames per second represented simply
>>>by 50 frames/sec.

>>You're confused. All Australian TV is 25 frames/sec. 576i still has
>>25 frames, except each frame is displayed twice, with half the picture
>>information contained in each 'field' (a total of 50 fields). 576p
>>on the other hand is 25 frames/sec, with each frame containing the
>>full picture information. It is not 50 frames/sec as you state.


> He isn't confused, for 7,ABC and SBS to allow 576p to be called "high
> definition" it is actually 50frames/sec. They simply double every frame up
> to achieve this, you can see this if you capture a bit of these channels and
> then step through frame by frame and see that each frame repeats once.
> (What would be really really cool is if they sourced 50frames/sec
> progressive cameras, then sport like golf, tennis etc would look awesome!).

Actually I had a look at the SBS HD coverage of the ashes and
it looked like true 50 fps to me, certainly it didn't seem to be
same doubling trick you get when recording at other times. I store
cricket as mpeg-4 and unfortunately only just have enough firepower
to get through a test at 25 fps so didn't really investigate it more.

[Ext User(Andy Weir)]

I did a couple of test recordings last night after installing the ATI 5.12
driver and for the first time was able to watch 9 HD without any significant
pausing.

9HD was 1920x1088, 23.524fps, 15,250 bitrate MPEG2 Field B. Audio was
identified Dolby Digital @ 448kbs(?) in this case.

7HD 720x576 50fps 9,000 bitrate

SD usually records at 720x576 25fps 6000 bitrate and sometimes mentions
Field A

Andy

[Ext User(Fred At Home)]

"David Z" <dave@hotmail.com> wrote in message
news:CSzof.16877$V7.10085@news-server.bigpond.net.au...
> "bill" <user@example.net> wrote in message
> news:dnuglm$2lj$1@otis.netspace.net.au...
>> Mike wrote:
>>> David Z wrote:
>>>
>>>>> As far as I know, please correct me if I'm wrong, 576i is 50
>>>>> interlaced fields per second represented by 25 digital frames/sec
>>>>> where as 576p is 50 progressive frames per second represented simply
>>>>> by 50 frames/sec.
>>>>
>>>>
>>>>
>>>> You're confused. All Australian TV is 25 frames/sec. 576i still has
>>>> 25 frames, except each frame is displayed twice, with half the picture
>>>
>>>
>>> Actually, you are both right sometimes.
>>> Interlaced TV is 50 fields/second. If shot on film, it is as David days,
>>> with 25 frames split into 50 fields.
>>> But on video, its better than that. Its usually shot 50 "frames" a
>>> second, so the second field is recorded it time in between the fields on
>>> either side. On a CRT display, the human eye will percieve smoother
>>> motion than if it was show on film at 24 (or 25) fps.
>>>
>>> On a digital display, a computer must de-interlace. It could in theory
>>> interpolate to 50 fps. (Q) Do many LCD or plasmas do that?
>>> My de-interlacer just generates 25 fps.
>>>
>>>> 576p on the other hand is 25 frames/sec, with each frame containing
>>>> the full picture information. It is not 50 frames/sec as you state.
>>>
>>>
>>> Oh yes it is. Except that most of the time, the source is 25fps, so
>>> 576p shows pairs of identical frames. Even the 7 HD demo loop
>>> shows every frame twice. (I single-stepped it on the PC)
>>>
>>
>> So in the end the perfect format for movies is really 1080i since movies
>> have little benefit from being shown in 576p since it is just displaying
>> each frame twice.
>>
>> Where as with 1080i there is an increase in resolution and no wasted
>> frames. So why do Seven bother with 576p, I guess it baffles us all..
>
> Actually 720p is better as there is apparantly more 'perceived'
> resolution. That is, 720p looks more impressive to most people than 1080i.
> Its a shame the format isn't widely used here, and that it won't be used
> on HD-DVD either.

I concur. I have a DVD player (Oppo) that upscales to both 720p and 1080i.
Playing DVDs at 720p looks appreciably better than HDTV from Nine, but DVD
at 1080i is not as good. In fact 720p looks incredible on a 52" DLP RPTV.
Friends with HD Plasmas appreciate the PQ.