Need Advice in Capturing VHS Video to MPEG

[Guest]

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I have some VHS videos that I recorded using expanded recording (EP),
and I have already transferred them into miniDV tapes. I have tried
capturing them into AVI files in hard disk using Ulead Video Studio 7
SE. But when I convert them into MPEG-1 or MPEG-2 files, I find that
their file size is way too big (20 minutes video takes 1.2 GB in MPEG
file (the original AVI file of the 20 minutes video is around 4 GB)).
I think the settings for capturing and rendering are probably too
high. I am wondering what settings to use in order to get a reasonably
good video and use relatively little storage space.

I was using 720x480 resolution and more than 8000 bitrate to capture
the video and render the MPEG file. According to messages posted here,
I am supposed to use 352x480 resolution and something like 4000
bitrate to get good video while keeping the file size small. I intend
to do this in this evening; but I have two questions:

- Should I use the low setting for both capturing video from miniDV
to AVI, and rendering from AVI to MPEG? Or should I use the high
setting (720x480 at above 8000) for capturing into AVI, and use the
low setting (352x480 at 4000) in rendering into MPEG? By the way, I
don't intend to keep the AVI file, I only use it as a way to get the
MPEG file.

- Some messages indicated that I will get a smaller file size if I
choose MPEG-1 instead of MPEG-2. But the result in my test (using high
setting in both capturing and rendering) only show a 2% reduction in
file size. Is this all I can expect from using MPEG-1 file? What's the
trade off between using MPEG-1 and MPEG-2 anyway?

Thanks in advance for any suggestion.

Jay Chan

 

[Guest]

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Jay Chan wrote:
> - Should I use the low setting for both capturing video from miniDV
> to AVI, and rendering from AVI to MPEG? Or should I use the high
> setting (720x480 at above 8000) for capturing into AVI, and use the
> low setting (352x480 at 4000) in rendering into MPEG? By the way, I
> don't intend to keep the AVI file, I only use it as a way to get the
> MPEG file.

Assuming you're using firewire, it's not really a "capture" from the
camera, but more of a transfer. What you end up with on your PC
should be identical to what you've got on tape. There shouldn't be any
"high" or "low" setting with respect to the process of moving the video
from your DV tape onto the PC. DV is fixed bitrate.

Go ahead and grab the DV video from the camera (into AVI format), and
then render it into MPEG2 of your liking. (Half D1 at 4000 sounds
reasonable to me)


> - Some messages indicated that I will get a smaller file size if I
> choose MPEG-1 instead of MPEG-2. But the result in my test (using high
> setting in both capturing and rendering) only show a 2% reduction in
> file size. Is this all I can expect from using MPEG-1 file? What's the
> trade off between using MPEG-1 and MPEG-2 anyway?


MPEG1 does not have the ability to represent interlaced video. If
you're using the full vertical resolution (480 lines with NTSC), then by
all means use MPEG2.


-WD


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[Guest]

Archived from groups: rec.video.desktop (More info?)

> Assuming you're using firewire, it's not really a "capture" from the
> camera, but more of a transfer. What you end up with on your PC
> should be identical to what you've got on tape. There shouldn't be any
> "high" or "low" setting with respect to the process of moving the video
> from your DV tape onto the PC. DV is fixed bitrate.
>
> Go ahead and grab the DV video from the camera (into AVI format), and
> then render it into MPEG2 of your liking. (Half D1 at 4000 sounds
> reasonable to me)

Thanks for correcting me that I should not need to play around with
high/low settings when I capture the video from miniDV source. This
saves me one variable to test with. I will try two 480 lines
variations (720x480, 352x480) with various bitrates to see which
setting of rendering will give me the best compromise in term of
quality and file size.

By the way, which bitrates would you suggest for rendering at 720x480
and 352x480 resolutions?

> MPEG1 does not have the ability to represent interlaced video. If
> you're using the full vertical resolution (480 lines with NTSC), then by
> all means use MPEG2.

Good to know that. I will stick with MPEG-2. The file size saving is
so small that this doesn't worth my time and effort to try MPEG-1.
This saves me one variable to test with.

Jay Chan

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

Jay Chan wrote:
>
> Thanks for correcting me that I should not need to play around with
> high/low settings when I capture the video from miniDV source. This
> saves me one variable to test with. I will try two 480 lines
> variations (720x480, 352x480) with various bitrates to see which
> setting of rendering will give me the best compromise in term of
> quality and file size.

The software shouldn't even give you the option. DV is 3.6MB/sec,
720x480 (NTSC). If it lets you select any other setting than that for
capture, I don't know what it's doing. (capturing and re-rendering at
the same time perhaps?)

> By the way, which bitrates would you suggest for rendering at 720x480
> and 352x480 resolutions?

It depends on how much you need to fit on a disc. When I make DVDs, I
usually use Half D1 @ 3000. That lets me put just over 3 hours on a
single disc. Depending on the quality of your source, encoder, and
what filters you're using, you may want to increase the bitrate to get
acceptable results. See:
http://dormcam.mine.nu:8080/restest

All of those samples are filtered with virtualdub. Ideally, I should
have used the highest bitrate possible for my source file, but you
should still get the idea. I think it was a 5000kbit MPEG2 from my
PVR-250. See http://mythhelper.sourceforge.net if you want to get the
filters and presets that I use. (Just grab the source code ZIP for the
presets)


-WD


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[Guest]

Archived from groups: rec.video.desktop (More info?)

On 11 May 2004 05:44:36 -0700, jaykchan@hotmail.com (Jay Chan) wrote:

>I will try two 480 lines
>variations (720x480, 352x480) with various bitrates to see which
>setting of rendering will give me the best compromise in term of
>quality and file size.
>
>By the way, which bitrates would you suggest for rendering at 720x480
>and 352x480 resolutions?

Encoding quality can be measured in bits/pixel. 352x480 (half D1) has
about half the pixels of 720x480 (full D1), and thus only requires
half the bits for the same encoding quality. IOW, 352x480 at 4000
kbps is aprox. equivalent to 720x480 at 8000 kbps -only the image is
somewhat less sharp, because of the reduced horizontal resolution.

Now, a usual way of encoding D1 is CQ 65%, which usually revolves
around 8500 kbps. What I would do is preparing a small half D1 clip,
and encoding it at increasing CQ from 65% up: 65%, 70%, 75%, 80%, 85%,
90%. Then notice the results, and decide by yourself. IMO, half D1 at
CQ 85% may be undistinguishable from D1 at CQ 65% for many people -but
the bitrate is substantially lower.

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

> The software shouldn't even give you the option. DV is 3.6MB/sec,
> 720x480 (NTSC). If it lets you select any other setting than that for
> capture, I don't know what it's doing. (capturing and re-rendering at
> the same time perhaps?)

Actually, I am following a tutorial that is available in internet on
the way to capture and rendering using Ulead Video Studio. That
tutorial established the high-setting in the project properties before
going on to talk about capturing. That gave me an impression that the
high-setting is for capturing. Now, I think about this, I have a
feeling that I might have understand this incorrectly. The high seting
in the project properties may not have to do with capturing; they are
being done one after the other may just be a coincidence.

> It depends on how much you need to fit on a disc. When I make DVDs, I
> usually use Half D1 @ 3000. That lets me put just over 3 hours on a
> single disc. Depending on the quality of your source, encoder, and
> what filters you're using, you may want to increase the bitrate to get
> acceptable results. See:
> http://dormcam.mine.nu:8080/restest

Good to know that. I will use 3000 bitrate at the starting point, and
adjust the bitrate upward until I cannot see much improvement or until
the file size is too big. I am going to try 3000, 4000, 5000 bitrates.

3 hours video in one DVD should be more than enough for my purpose. I
am happy to just to fit 1.5 hour of video in one DVD. This means I
have some room to increase the bitrate. Thanks.

> PVR-250

Great! I will receive my order of PVR-250 TV tuner card very soon. I
hope I can use the hardware encoder in it to speed up the rendering
process. This sounds very promising. May I ask how long did you take
to render the video into MPEG using your PVR-250?

Jay Chan

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

> Encoding quality can be measured in bits/pixel. 352x480 (half D1) has
> about half the pixels of 720x480 (full D1), and thus only requires
> half the bits for the same encoding quality. IOW, 352x480 at 4000
> kbps is aprox. equivalent to 720x480 at 8000 kbps -only the image is
> somewhat less sharp, because of the reduced horizontal resolution.

Thanks for sharing this info. This means I really don't need to try
bitrate near as high as 8000 if I set the resolution as 352x480. This
saves me one test case to try.

> Now, a usual way of encoding D1 is CQ 65%, which usually revolves
> around 8500 kbps. What I would do is preparing a small half D1 clip,
> and encoding it at increasing CQ from 65% up: 65%, 70%, 75%, 80%, 85%,
> 90%. Then notice the results, and decide by yourself. IMO, half D1 at
> CQ 85% may be undistinguishable from D1 at CQ 65% for many people -but
> the bitrate is substantially lower.

May I ask what is "CQ", and what is the percentage 65%...90% means? I
probably don't need this info right now for rendering those relatively
low quality VHS videos that I am doing now. But I will likely need
this info when I start copying my wedding video and my kid videos from
Hi8 to DVD -- I will need to get very high quality rendering, not just
"good enough".

Thanks in advance for any further info on this issue.

Jay Chan

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

Jay Chan wrote:
>
> high-setting is for capturing. Now, I think about this, I have a
> feeling that I might have understand this incorrectly. The high seting
> in the project properties may not have to do with capturing; they are
> being done one after the other may just be a coincidence.

That's probably the case.


> Good to know that. I will use 3000 bitrate at the starting point, and
> adjust the bitrate upward until I cannot see much improvement or until
> the file size is too big. I am going to try 3000, 4000, 5000 bitrates.

Sounds like a plan. I use AC3 for my audio, too. LPCM takes up way
too much space, and MPEG2 audio isn't a requirement for the NTCS spec.
(Though the compatibility is there most of the time)


> Great! I will receive my order of PVR-250 TV tuner card very soon. I
> hope I can use the hardware encoder in it to speed up the rendering
> process. This sounds very promising. May I ask how long did you take
> to render the video into MPEG using your PVR-250?

The PVR-250 doesn't accelerate the rendering in any way. It can capture
directly into MPEG2 format. I have one in my MythTV machine, and I
take the recordings and re-render them (minus commercials) on my Windows
machine. Aside from removing commercials, the other reason I re-render
them is so that I can use VirtualDub filters for further noise reduction
so that I can use a lower bitrate and still have acceptable results.
(along with resampling into Half D1 resolution)

In your case, it may make more sense to use the PVR-250 to capture
directly into your final format. (and skipping the intermediate DV step)
Just pick the bitrate you like and you'll be able to use the hardware
encoder in real time. With the filters and settings I use, it takes
about 3.5 hours to encode 23 minutes of video on my Athlon XP 1800. I
haven't used the PVR-250 under windows, but I would assume that you will
have control over bitrate, resolution, and other capture features.


-WD


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[Guest]

Archived from groups: rec.video.desktop (More info?)

I have rendered an one-minute medium-to-low quality VHS video clip
into MPEG-2 files in various rendering settings. The good thing is
that the file size is quite small if I choose a low bitrate. The
strange thing is that the file sizes for 352x480 and 720x480
resolutions are very close; actually in most test cases, the file size
for 352x480 is actually greater than that's for 720x480 -- I expect
the file size of 352x480 should be almost half of the file size for
720x480. See below:

KB for Each
Minute of
Resolution BitRate Video Clip
---------- ------- -----------

352x480 3000 21,325
4000 27,809
5000 33,753
8264 56,881

720x480 3000 20,739
4000 27,719
5000 34,531
8264 54,733

(The original video clip is 210 MB; the rendering process reduces it
to as little as 1/10 of the original size).

I have a couple questions on this if you don't mind:

- Do you know why using 720x480 doesn't increase the file size?

- Does this have to do with the fact that the video clip is only one
minute long and may not be long enough to be a good test case? I would
have tried a longer video clip for testing; but I don't know how long
is long enough.

- Does this have to do with the fact that the original video clip is
relatively low quality (VHS video recorded at EP mode not SP mode) and
set the horizontal resolution to high doesn't add anything new to the
rendered video and simply got compressed away?

Thanks in advance for any further info on this strange problem.

By the way, I also have another post called "Put Different
Resolution/Bitrate Video Clips in One DVD?" that is sort-of related to
this post. Is this possible for you to also take a look on that post?
Thanks again.

Jay Chan

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

Jay Chan wrote:

> I have a couple questions on this if you don't mind:
>
> - Do you know why using 720x480 doesn't increase the file size?

File size is a factor of bitrate and running time *only*. If two equal
length videos use the same bitrate, they will take up the same amount of
space regardless of resolution. Using a lower resolution means that
more bits will be used to represent each pixel, since there are less of
them.


-WD

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On 13 May 2004 05:06:20 -0700, jaykchan@hotmail.com (Jay Chan) wrote:

>The
>strange thing is that the file sizes for 352x480 and 720x480
>resolutions are very close

As Will Dorman tells you, final file size is = Bitrate x Time. That's
what bitrate means, after all. It's a size per time measure; bits
(kilobits, bytes, Mb... whatever) per second (minute, hour...
whatever).

That's why you can know beforehand the final size of your mpeg when
encoding in CBR or VBR mode. In the case of VBR, what applies is the
average bitrate.

But it's a different case when you encode in CQ mode. Then, the lower
the resolution, the less bits you need to encode it at the same given
quality. Only, you do not know beforehand how many bits does the
encoding require. It may be easier to understand if you think it in
terms of a Jpeg image. These are compressed in CQ mode. You cannot
know beforehand the size of the compressed image from a BMP one. You
only know, the bigger the resolution the bigger the file size you get.
And movies are, after all, but a series of images. Only, movies use to
be encoded in CBR to ensure the player can cope with them, and to
ensure they fit on a disc. When those concerns do not apply, one can
encode in CQ mode. In the case of 352x480, CQ makes more sense,
because you are not going to violate the max. bitrate allowed by DVD
standard. But if you need an exact file size, you would stick to VBR.
On the other hand, at 720x480 if you want the highest quality/bitrate,
you can do that with CBR, which needs only 1 encoding pass, because
you cannot play with higher bitrates without surpassing the DVD
limits. While at a lower quality (say, 6000 kbps) one would use VBR
(which needs more than 1 pass) for the best results, at the expense of
encoding time.

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

> As Will Dorman tells you, final file size is = Bitrate x Time. That's
> what bitrate means, after all. It's a size per time measure; bits
> (kilobits, bytes, Mb... whatever) per second (minute, hour...
> whatever).

Thanks both of you to explain the reason why the file sizes are the
same at a given bitrate. This puts me at ease.

> But it's a different case when you encode in CQ mode. Then, the lower
> the resolution, the less bits you need to encode it at the same given
> quality. Only, you do not know beforehand how many bits does the
> encoding require. ... Only, movies use to be encoded in CBR to ensure
> the player can cope with them, and to ensure they fit on a disc. When
> those concerns do not apply, one can encode in CQ mode. In the case of
> 352x480, CQ makes more sense, because you are not going to violate the
> max. bitrate allowed by DVD standard.

I don't really need to know the file size in advance. Seem like I may
want to try CQ mode just to see if it can save me even more space. But
there is one question: What's "CQ mode"? Does this mean "Constant
Quality"? I am trying to find this mode in my Ulead Video Studio 7 SE.

Thanks.

Jay Chan

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On 14 May 2004 08:52:46 -0700, jaykchan@hotmail.com (Jay Chan) wrote:

>What's "CQ mode"? Does this mean "Constant
>Quality"?

In the case of Tmpgenc, it's "Constant Quality". For other encoders it
might be "Constant Quantizer", which is about the same -only it goes
in opposite direction. The higher the quantizer, the lower the
quality. Quality is measured in %, while the quantizer measures how
much information is discarded. The DivX codec configuration shows both
quality and quantizer.

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

"Jay Chan" <jaykchan@hotmail.com> wrote in message
news:c7e5acb2.0405120852.68a553b0@posting.google.com...
> > Encoding quality can be measured in bits/pixel. 352x480 (half D1) has
> > about half the pixels of 720x480 (full D1), and thus only requires
> > half the bits for the same encoding quality. IOW, 352x480 at 4000
> > kbps is aprox. equivalent to 720x480 at 8000 kbps -only the image is
> > somewhat less sharp, because of the reduced horizontal resolution.
>
> Thanks for sharing this info. This means I really don't need to try
> bitrate near as high as 8000 if I set the resolution as 352x480. This
> saves me one test case to try.
>
> > Now, a usual way of encoding D1 is CQ 65%, which usually revolves
> > around 8500 kbps. What I would do is preparing a small half D1 clip,
> > and encoding it at increasing CQ from 65% up: 65%, 70%, 75%, 80%, 85%,
> > 90%. Then notice the results, and decide by yourself. IMO, half D1 at
> > CQ 85% may be undistinguishable from D1 at CQ 65% for many people -but
> > the bitrate is substantially lower.
>
> May I ask what is "CQ", and what is the percentage 65%...90% means? I
> probably don't need this info right now for rendering those relatively
> low quality VHS videos that I am doing now. But I will likely need
> this info when I start copying my wedding video and my kid videos from
> Hi8 to DVD -- I will need to get very high quality rendering, not just
> "good enough".
>
> Thanks in advance for any further info on this issue.
>
> Jay Chan

I remember suggestions some time back that buying a video camera would be a
cost-effective way to put videos onto a HD on the way to DVDs.

Any suggestions for video cameras now? My WinTV card seems to have got some
bug - SARS maybe. Have just reinstalled the drivers and software 5 times in
a row and still nothing

TIA

Sd