mpeg4 quality

Catbed · 13-04-2007, 15:31

Got a Panasonic plasma with a memory card slot. I was thinking this might be useful to record the odd programme when the PVR is already fully used. Today I borrowed the SD card from my camera just to try it out before ordering a GB capacity card for the TV.

Long story short - the quality is rubbish. I thought mpeg4 was one of the systems used by DTT anyway, so was expecting similar quality, but even on the finest setting the picture is well fuzzy and far below the quality of the Freeview programme it was recorded from.

Has anyone else tried out this function? Is this normal?

Adam D · 13-04-2007, 15:34

If the program was encoded in Mpeg4 the bitrate might not be high.

eg. Mp3's bit rate normally 128 when lowerd to 64 the file is still Mp3 but less quality.

The more quality the more space aswell.

meltcity · 13-04-2007, 20:57

It's just a gimmick. The encoder probably costs pennies and records at very low resolution.

XviD, which is a form of MPEG4, is used widely for ripping TV programmes and the quality can be near broadcast quality, even with files as small as 350MB for a 42 minute recording. Interlaced video content seems to cause problems for the rippers (no problem with the codec itself though).

MPEG4 is not used in DTT SD broadcasts, although a variant, H.264, is used by SkyHD channels and it was also used on the BBC's HD trial on DTT in London.

daveac · 14-04-2007, 00:15

Quote:

Originally Posted by Catbed

Got a Panasonic plasma with a memory card slot. I was thinking this might be useful to record the odd programme when the PVR is already fully used. Today I borrowed the SD card from my camera just to try it out before ordering a GB capacity card for the TV.

Long story short - the quality is rubbish. I thought mpeg4 was one of the systems used by DTT anyway, so was expecting similar quality, but even on the finest setting the picture is well fuzzy and far below the quality of the Freeview programme it was recorded from.

Has anyone else tried out this function? Is this normal?

But it might be the speed of the memory card thats limiting things rather than the codec.

Cheers, daveac

Catbed · 14-04-2007, 11:54

Adtech
I recorded a snippet of programe I was watching, then played it back. I expected the playback to be nearly as good as the live - it's digital, innit?

Meltcity
Thanks for the info. It sounds like mpeg4 isn't the problem, but as you suggest, maybe it's converting from one codec/signal type to another that is screwing it.

Daveac
I followed the 'compatability' link in the manual to the Panasonic website and it suggests that both normal and fast SD cards are OK. I certainly ain't splashing out on a fast one just to test that idea - I can live without the feature

I may pop an e-mail off to Panasonic to see what their take on it is.

14-04-2007, 12:08

Wouldn't you need a large memory card to record a decent amount of material?

Just going by some of the SD recordings on Sky.

A SD recording taking just 1%, roughly 1/2hr, would need a 2Gb of memory. 1hr HD at 6% you would need 10Gb.

Or am I on the wrong track?

daveac · 14-04-2007, 13:44

Quote:

Originally Posted by TommyW

Wouldn't you need a large memory card to record a decent amount of material?

Just going by some of the SD recordings on Sky.

A SD recording taking just 1%, roughly 1/2hr, would need a 2Gb of memory. 1hr HD at 6% you would need 10Gb.

Or am I on the wrong track?

But those won't be MPEG4 recordings.

Also I think you can have lower quality MPEG4 recordings that use a reduced resolution to bring the bit rate even lower.

Cheers, daveac

skinj · 14-04-2007, 14:57

The mpeg recording on the Panasonic plasmas upto the 60/600 range is designed for playback on handheld/portable devices, not the tv itself. The quality is low to allow a large amount of recording for personal devices.
Also its designed to allow mpeg4 recorded on a personal to be played back!

Catbed · 14-04-2007, 21:27

Ah. Now that makes some sense, skinj.

Even on the finest setting the manual says you can get about 1h 50m on a 1GB card. I thought that seemed a bit to good to be true.

I tried putting some stills up via the SD card this afternoon. I took a few snaps round the house and garden, put the SD card into the TV and displayed them. Considering the camera takes 6M pixel pictures which look fantastic on the PC or print, the Panasonic is rubbish

. They look like they were downscaled to about 480x300 and then upscaled to the TV resolution.

Orbitalzone · 14-04-2007, 22:29

Quote:

Originally Posted by Catbed

.....................I expected the playback to be nearly as good as the live - it's digital, innit?

.

A common misconception!

Digital means almost nothing with regard to a level of quality, digital audio can mean studio quality or a very fuzzy, mono mp3 audio track that sounds worse than a telephone conversation.

VideoCD was digital but looks pretty poor, DVD on the other hand is also digital but looks very good... and so on.

THe manufacturers have played on this misuse of the word 'digital' and everything electronic mentions it to make it sound impressive.

13-04-2007, 15:31	#1
Catbed Forum Member Join Date: Nov 2005 Location: Cheshire, Winter Hill TX Posts: 339	mpeg4 quality Got a Panasonic plasma with a memory card slot. I was thinking this might be useful to record the odd programme when the PVR is already fully used. Today I borrowed the SD card from my camera just to try it out before ordering a GB capacity card for the TV. Long story short - the quality is rubbish. I thought mpeg4 was one of the systems used by DTT anyway, so was expecting similar quality, but even on the finest setting the picture is well fuzzy and far below the quality of the Freeview programme it was recorded from. Has anyone else tried out this function? Is this normal?

13-04-2007, 20:57	#3
meltcity Forum Member Join Date: Nov 2003 Posts: 1,770	It's just a gimmick. The encoder probably costs pennies and records at very low resolution. XviD, which is a form of MPEG4, is used widely for ripping TV programmes and the quality can be near broadcast quality, even with files as small as 350MB for a 42 minute recording. Interlaced video content seems to cause problems for the rippers (no problem with the codec itself though). MPEG4 is not used in DTT SD broadcasts, although a variant, H.264, is used by SkyHD channels and it was also used on the BBC's HD trial on DTT in London. Last edited by meltcity : 13-04-2007 at 21:00.

13-04-2007, 15:34	#2
Adam D Forum Member Join Date: Jan 2007 Location: UK, Posts: 4,939	If the program was encoded in Mpeg4 the bitrate might not be high. eg. Mp3's bit rate normally 128 when lowerd to 64 the file is still Mp3 but less quality. The more quality the more space aswell.

14-04-2007, 00:15	#4
daveac Forum Member Join Date: Oct 2006 Location: Manchester UK Posts: 466	Quote: Originally Posted by Catbed Got a Panasonic plasma with a memory card slot. I was thinking this might be useful to record the odd programme when the PVR is already fully used. Today I borrowed the SD card from my camera just to try it out before ordering a GB capacity card for the TV. Long story short - the quality is rubbish. I thought mpeg4 was one of the systems used by DTT anyway, so was expecting similar quality, but even on the finest setting the picture is well fuzzy and far below the quality of the Freeview programme it was recorded from. Has anyone else tried out this function? Is this normal? But it might be the speed of the memory card thats limiting things rather than the codec. Cheers, daveac

14-04-2007, 11:54	#5
Catbed Forum Member Join Date: Nov 2005 Location: Cheshire, Winter Hill TX Posts: 339	Adtech I recorded a snippet of programe I was watching, then played it back. I expected the playback to be nearly as good as the live - it's digital, innit? Meltcity Thanks for the info. It sounds like mpeg4 isn't the problem, but as you suggest, maybe it's converting from one codec/signal type to another that is screwing it. Daveac I followed the 'compatability' link in the manual to the Panasonic website and it suggests that both normal and fast SD cards are OK. I certainly ain't splashing out on a fast one just to test that idea - I can live without the feature I may pop an e-mail off to Panasonic to see what their take on it is.

14-04-2007, 12:08	#6
TommyW Posts: n/a	Wouldn't you need a large memory card to record a decent amount of material? Just going by some of the SD recordings on Sky. A SD recording taking just 1%, roughly 1/2hr, would need a 2Gb of memory. 1hr HD at 6% you would need 10Gb. Or am I on the wrong track?

14-04-2007, 13:44	#7
daveac Forum Member Join Date: Oct 2006 Location: Manchester UK Posts: 466	Quote: Originally Posted by TommyW Wouldn't you need a large memory card to record a decent amount of material? Just going by some of the SD recordings on Sky. A SD recording taking just 1%, roughly 1/2hr, would need a 2Gb of memory. 1hr HD at 6% you would need 10Gb. Or am I on the wrong track? But those won't be MPEG4 recordings. Also I think you can have lower quality MPEG4 recordings that use a reduced resolution to bring the bit rate even lower. Cheers, daveac

14-04-2007, 14:57	#8
skinj Forum Member Join Date: Nov 2001 Posts: 3,206	The mpeg recording on the Panasonic plasmas upto the 60/600 range is designed for playback on handheld/portable devices, not the tv itself. The quality is low to allow a large amount of recording for personal devices. Also its designed to allow mpeg4 recorded on a personal to be played back!

14-04-2007, 21:27	#9
Catbed Forum Member Join Date: Nov 2005 Location: Cheshire, Winter Hill TX Posts: 339	Ah. Now that makes some sense, skinj. Even on the finest setting the manual says you can get about 1h 50m on a 1GB card. I thought that seemed a bit to good to be true. I tried putting some stills up via the SD card this afternoon. I took a few snaps round the house and garden, put the SD card into the TV and displayed them. Considering the camera takes 6M pixel pictures which look fantastic on the PC or print, the Panasonic is rubbish . They look like they were downscaled to about 480x300 and then upscaled to the TV resolution.

14-04-2007, 22:29	#10
Orbitalzone Forum Member Join Date: Oct 2000 Location: Sussex Posts: 12,173	Quote: Originally Posted by Catbed .....................I expected the playback to be nearly as good as the live - it's digital, innit? . A common misconception! Digital means almost nothing with regard to a level of quality, digital audio can mean studio quality or a very fuzzy, mono mp3 audio track that sounds worse than a telephone conversation. VideoCD was digital but looks pretty poor, DVD on the other hand is also digital but looks very good... and so on. THe manufacturers have played on this misuse of the word 'digital' and everything electronic mentions it to make it sound impressive.

DS Forums

mpeg4 quality