DVD max. video bitrate

[geohei]

Hi.

Two questions regarding the max. DVD bitrate.

1. It's supposed to be 9.8 Mbps = 10035 kbps (audio+video). Most encoding software (MainConcept PPRO encoder, TMPGEnc, ...) suggests 8000 Kbps as maximum setting. However when PCM is encoded with 1536 Kbps, this would leave 8499 Kbps for video. Hence the max. is 8499 Kbps and not 8000 Kbps. Is that correct?

2. How does a standalone DVD player notice a higher than 9.8 Mbps bitrate? Is the stream analysed and the bitrate measured, or is the MPEG-2 header read and the stored bitrate used to determine whether the DVD player plays the stream or not.

Many thanks.

[Capmaster]

Hi.

Two questions regarding the max. DVD bitrate.

1. It's supposed to be 9.8 Mbps = 10035 kbps (audio+video). Most encoding software (MainConcept PPRO encoder, TMPGEnc, ...) suggests 8000 Kbps as maximum setting. However when PCM is encoded with 1536 Kbps, this would leave 8499 Kbps for video. Hence the max. is 8499 Kbps and not 8000 Kbps. Is that correct?

2. How does a standalone DVD player notice a higher than 9.8 Mbps bitrate? Is the stream analysed and the bitrate measured, or is the MPEG-2 header read and the stored bitrate used to determine whether the DVD player plays the stream or not.

Many thanks.

First - I think they're referring to ballpark figures. I use 9800 as a max and have for a long time. I believe the 8000 mentioned is just a rule of thumb and not a hard and fast number.

Typically you will use VBR, set the avg. bitrate at something like 6000 or 6500, and the peak at 9800.

My Panasonic standalone caps all the way up to 15000, but that's not officially compliant. It's compliant for MPEG2, but not true DVD. DVD tops out at 9800. My players read 15000, but some might not.

Second - You ought to reconsider using PCM for the audio. It's basically uncompressed WAV and is an old, old format, although highly compatible. Stick with MPEG1-Layer 2 (MP2) or AC3 (Dolby Digital) audio. It sounds just as good if not better, and takes up a fraction of the DVD space as PCM.

[sacajaweeda]

I like the PCM tracks that a lot of concert videos have on them. They are great for ripping and splitting the wavs up then making your own audio CDs with.

[Cornucopia]

My Pioneer PRV-9000 tops out at 9300 kbps (MPEG2 Video) / 256 kbps (AC3 Audio).
and I KNOW it's compliant!

The rule of thumb used to be ~8000kbps for video, mainly to make it easy on the early DVD settop players that were lacking in speed and buffer capability. This rule should have been eased off a great deal by now, what with most new DVD decoder chips using extra speed and buffer sizes for trick stuff like multi-speed, zooming, etc.

The actual rule is that the total combined streams of the payload (which doesn't include the navigation info) should be up to 10.08Mbps, with 9.8Mbps being the top rate of the video stream.

You can always work backwards--try it as high as it will go, test it on an RW: if it doesn't work, back off a little and try again. Then you'll know for sure what the top capability of your player(s) is/are. Then encode for that.
Players are bound to continue to get better in this respect, not worse. (God, I hope not! )

Scott

[geohei]

First - I think they're referring to ballpark figures. I use 9800 as a max and have for a long time. I believe the 8000 mentioned is just a rule of thumb and not a hard and fast number.

Typically you will use VBR, set the avg. bitrate at something like 6000 or 6500, and the peak at 9800.

But in this case, 9800 Kbps video would only leave 235 Kbps for audio (assuming that the max. total audio+video bitrate is 10035 Kbps), right?

My Panasonic standalone caps all the way up to 15000, but that's not officially compliant. It's compliant for MPEG2, but not true DVD. DVD tops out at 9800. My players read 15000, but some might not.

I believe you mix up Mbps and Kbps here. When you talk about "9800", do you mean 9.8 Mbps or 9800 Kbps, which is not the same?

Second - You ought to reconsider using PCM for the audio. It's basically uncompressed WAV and is an old, old format, although highly compatible. Stick with MPEG1-Layer 2 (MP2) or AC3 (Dolby Digital) audio. It sounds just as good if not better, and takes up a fraction of the DVD space as PCM.

Which AC3 encoder should I use?

[geohei]

The actual rule is that the total combined streams of the payload (which doesn't include the navigation info) should be up to 10.08Mbps, with 9.8Mbps being the top rate of the video stream.

I guess you mean 9.8 Mbps is the top rate for audio+video, correct?

You can always work backwards--try it as high as it will go, test it on an RW: if it doesn't work, back off a little and try again. Then you'll know for sure what the top capability of your player(s) is/are. Then encode for that.

Actually, I need compliant DVDs which run on many players (not able to test them all). Hence, I would like to be compliant.

Therefore, I was interested to learn more about which criteria are used by a standalone DVD player to determine whether or not a bitrate exceeds player limits. Is it the real measured audio+video bitrate, or just the header of the MPEG-2 stream?

TIA

[adam]

1) The max video bitrate limit is 9.8Mbits. The total max bitrate (audio + videe) is 10.08Mbits. These values are listed in DVD Mystified and other DVD related books. Its also strictly used by Scenarist. The sugested values in programs like TMPGenc are just that, suggested values. I have had no luck getting TMPGEnc to adhere to my max bitrate settings. I imagine those are conservative numbers it gives to ensure compliance.

2) I doubt any DVD players check bitrate for compliance. If the bitrate is out of spec then it will simply lead to more playback problems. DVD Authoring programs will obviously check bitrate for compliance. Some actually analyze the bitrate, some just read the header flags...and some do both.

[Cornucopia]

Just to clarify: I stated Max Video bitrate as supposed to be 9.8 Mbps. DVD DeMystified says it's supposed to be 9800 kbps. Small difference (2.5%), but it could bite somebody if they're not careful. Actually, this also answers that other question:

9800kbps Video + 448kbps AC3 Audio = 10.007Mbps, still less than 10.08Mbps limit!

Some cheap players probably don't check anything, just try to spit it out as fast as it can until it hits it's limit. Then it probably stutters & freezes.
I would guess that most players read the header, as it is there on all MPEG2 sequences. Of course, you CAN fool the player by putting in a different number. And some encoders put in the incorrect number, so its good to check it sometimes. Try ReStream for this.

Scott

[geohei]

I read in a french doc that 9.8 Mbps seems to be the real video limit. This would allow 224 Kbps as audio in order to remain below 10.08 Mbps total (audio+video) bitrate.

9.8 + 256/1024 = 10.050 < 10.080

Gonna try this setting.

Thanks a lot so far!

[SaSi]

Perhaps you also need to consider that many tests show that a descent MPEG encoder can encode full frame video at 8Mbps with unnoticable loss in quality compared to the original footage. Therefore, encoding video at higher bitrates is - perhaps - a waste.

I think the real issue is not the average bitrate (either CBR or VBR) but how the encoder handles peaks. Even if you configure the well known encoders to use 9800 as peak, very few will go that high, even in scenes that obviously demand it.

Using 9800 CBR will obviously give you that, but my point is that 8000 is probably more than enough - for typical material.

[geohei]

Sounds very logical.

I am going to test average 8000 with peaks 9000 and min. 7000.

Thanks.

[geohei]

One more question ... the max. bitrate of 10.08 Mbps audio+video, is this all audio tracks together (assuming there are more), or just the one used?

E.g. (all in Kbps) ...

video bitrate: 9000
audio mp2: 224
audio ac3: 224
audio pcm: 1536

total: 10984 Kpbs = 10.727 Mbps

Assuming I use ac3 (9.008 Mbps), is the max. bitrate of 10.08 Mbps exceeded or not?

TIA

[Baldrick]

all tracks together.

[geohei]

all tracks together.

Many thanks!