best codec for tv

[shadowhunter]

Hi all,

I got myself a tv-card, and I am asking you guys what the best codec is for tv (divx seems to create quite large files in gknot) but that isn't a problem now cause I got myself a dvd writer. what is the best:

-divX
-Xvid
-Mpeg2
-...

[echooff]

I'm not sure what you are asking. If you are going out to tv from your computer AFAIK what codec you use doesn't matter. If you are placing youe videos on dvd then it must be mpeg2.

[jggimi]

Welcome to the forum, Shadowhunter.

XviD and DivX are MPEG-4 codecs, DVD video streams are MPEG-2. But ... there is no such thing as "what's best." Everything is situational. It's one of the reasons we have Rule #12 (http://forum.doom9.org/forum-rules.htm). For a great example of why there are no hard and fast "best" answers, take a look at Doom9's MPEG-4 Codec Comparisons (http://www.doom9.org/codec-comparisons.htm).

You can either use an MPEG-4 codec or MPEG-2 if you elect to burn data DVDs. If you wish to burn Video DVDs, then you must conform to DVD standards, which include MPEG-2 as the video stream and require an additional step known as Authoring.

In either case, I recommend you start with Doom9's DVD Basics (http://www.doom9.org/dvd-basics.htm) for necssary background, then move to Doom9's Guides (http://www.doom9.org/guides.htm) for links to software and step-by-step instructions.

[shadowhunter]

I record video (tv-input) from my computer.
I only play it on my computer.
I got 4.5 gb storage space.

In divx you always lose quality.
Mpeg2 gives higher quality.
4.5 gb file of divx gives you an overall better output then mpeg2 or the other way a mpeg2 file gives you more quality, or this is movie specific, in this case please tell on which factors I got to pay attention to.

thx for your replies.

Geert.

[Tuning]

Capture in MPEG-2 and encode to MPEG-4 using VdubMod.(Idea ;) )

[jggimi]

I record video (tv-input) from my computer.
I only play it on my computer.
I got 4.5 gb storage space....

That's not a great deal of space for analog capture, which can often be in the range of 1 GB every 10 minutes, using a lossless codec such as HuffYUV at high resolution.

If you've not visited the Capturing forum (http://forum.doom9.org/forumdisplay.php?s=&forumid=10) I recommend a visit. There is a Capture FAQ (http://forum.doom9.org/showthread.php?s=&threadid=32575) and a Capture Guide (http://www.doom9.org/capture/start.html) there.

...In divx you always lose quality.
Mpeg2 gives higher quality....

You are misinformed.

Both MPEG-2 and MPEG-4 are lossy. There are many factors that affect perceived quality; bitrate, resolution, and compressibility are just a few.

Here are two examples where each type of video exceeds the quality of the other: MPEG-4 codecs are often used at significantly lower bitrates (less than 2000 kb/s) than, perhaps, higher quality DVDs, which can have combined stream bitrates near 10000 kb/s). This is to fit the video onto 1 or 2 (or sometimes 3) CDs. Not because MPEG-4 is lower quality than MPEG-2. Bitrate is the key factor.

SVCD encoders are making MPEG-2 video at higher bitrates (2000 kbps or so) than many DivX users, yet the perceived quality may be lower than DivX. Not because MPEG-2 has lower quality than MPEG-4. But because the resolution is anamorphic, and the content component is also smaller. Resolution is the key factor.One of the reasons you should never ask, "what's best."

... 4.5 gb file of divx gives you an overall better output then mpeg2 or the other way a mpeg2 file gives you more quality, or this is movie specific, in this case please tell on which factors I got to pay attention to.

Did I misunderstand your ...I got 4.5 gb storage space... comment? If that is the capacity for storage after conversion, rather than capture and conversion togther ... then here's a little math, using Gknot as my MPEG-4 calculator:

4.5 GB = 4608 MB = 4718592 KB
Assumptions: Single audio track, 160 kb/s vbr mp3
Video: D1 PAL: 768x576, 25fps
Container: AVI

60 minutes = 10565 kb/s, bits/pixels*frames = 0.842
90 minutes = 6986 kb/s, bits/pixels*frames = 0.557
120 minutes = 5196 kb/s, bits/pixels*frames = 0.414
150 minutes = 4122 kb/s, bits/pixels*frames = 0.329
180 minutes = 3406 kb/s, bits/pixels*frames = 0.272

I don't have an MPEG-2 calculator handy, but the bitrates are likely to be in a similar range.

Confusing things even further ... if you were to read through Doom9's MPEG-4 comparisons, you'll note that each codec has plusses and minuses that are very specific to content, and specific to bitrate.

And more confusion ... when it comes to MPEG-2, you are dependant on your choice of encoder and it's capabilities as well. The two most popular MPEG-2 encoders are TMPGEnc ($) and CCE SP ($$$). There has been much discussion about these two encoders, and the general consensus has been that CCE can produce higher quality results, though it's relatively expensive for home PC software.

Your question on what's "best" is unanswerable. However, I can tell you that MPEG-4 encoders can be free, whereas MPEG-2 encoders? As far as I know, bbMPEG has the only free MPEG-2 encoder, and I've never read any reviews of it.

[shadowhunter]

my software with tv-in comes with an mpeg2-encoder... so it is not a question of money.

But the codec choice would be the same, I lose only the some codecs lose other things than other codecs. like xvid should keep alot of detail.

768x576 seems to be quite high as resolution, at what resolution you get your incoming stream (if I can half these values will my file be 1/4 of it size)?

again thanks, and in case you did not know, I read most of the guides but it seems to be not enough.

[jggimi]

...768x576 seems to be quite high as resolution...

See the Capture FAQ, question #9.

...at what resolution you get your incoming stream...

Personally? I do NTSC capture, at 720x480, in HuffYUV. In post processing, the output is either MPEG-2 (SVCD) or DivX MPEG-4 (AVI), depending on the playback methodology desired. I've also been experimenting with XVCD, which is MPEG-1.

... (if I can half these values will my file be 1/4 of it size)?...

If your bitrate remains the same, the file will be the same size. The bits/pixel*frame will increase, as your pixels per frame will be 1/4 what they were.