So what format should I use?

[doublejj0305]

I'm very new to this... I have some DVD's that I want to burn to my hard-drive and then stream them to my Tivo HD using Stream-baby-Stream. I just upgraded to the V.4 of VRD. The majority of the time I will just be using this for Tivo stream but I might like to put them on a thumb drive occastionally and bring them to work to watch. My goals are to keep the 5.1 sound and have very minimal compression on the video. What format do you guys suggest that I use when I click "save as". Also is there any thing that you suggest changing in the option tab? Thanks for the help!

[Dan203]

The best quality, and fastest speed, will be achieved by simply saving the files as standard .mpg. However those are going to take more disc space and higher network bandwidth.

If you recode to H.264 you can cut the bitrate by 1/2-1/3 and retain the same quality. The only caveat is that as this first version or VRD v4 does not support AC3 audio in MP4 containers, and the only way StreamBaby supports H.264 is in an MP4 container. I just added AC3 support to our MP4 muxer yesterday, but it needs to go through some additional testing before we release it, so it's probably going to be a week or so before we have an update which will allow you to create the H.264 files you need.

Dan

[doublejj0305]

I think that is why I'm confused. i only see Ipod and PSP in MP4, I don't just see plain MPEG4 Program Stream (.*mp4) which is what I assume I need correct?

[Dan203]

You'll need to create your own profile for it. Go to Tools->Edit profile list... This is a list of all profiles offered for output when saving a file. You can use this dialog to add new ones, disable or delete existing ones, etc... For this project you would need to create a new profile which uses the "MP4 Generic" type. If you leave the audio format as "Auto" we will recode to AAC for now, but when the update comes it will retain AC3 audio if the source has it. (that way you wont have to mess with the profile after the update)

Dan

[doublejj0305]

Awesome!!! What do you suggest for audio and video bitrate which won't effect the original DVD.

Thanks for the quick response as well, I know you must be busy

[MrVideo]

Awesome!!! What do you suggest for audio and video bitrate which won't effect the original DVD.

You cannot change the bitrate for AC3 audio. Whatever the bitrate was use for the DVD is what you'll end up with in your final file. VRD cannot re-encode AC3 audio. To do so requires a very expensive license from Dolby Labs.

The shear nature of MPEG-2/H.264 re-encoding affects the original source. You cannot get a perfect copy of the original if you re-encode. You'll only very get perfect copies is if you only copy the source.

That said, MPEG-2/H.264 will survive through more re-encodes than making copies of a VHS tape to another VHS tape.

If you can work with H.264 video, by all means do so. H.264 has a 2:1 ratio over MPEG-2, in that MPEG-2 at 20 Mbps is generally equal to H.264 at 10 Mbps.

So, if your DVD is averaging 6 Mbps, in theory you can re-encode at 3 Mbps using H.264. You will probably get away with 2 Mbps. I've done many 720p H.264 re-encodes at 2.5 Mbps. While not flawless, it is amazing how good H.264 looks.

The general rule in the industry is that the source should be 2, or more, times the bitrate of the result. Don't foget the 2:1 MPEG-2/H.264 ratio. This is not the place to explain what goes on when your re-encode at less than the 2:1 ratio (input to output).

[moyekj]

Just evaluating this a little tonight. Good to see that MP4 container with AC3 audio will be forthcoming.

However MP4 container with H.264 only gives me option for resolution up to 720x480 whereas TS container I can get up to 1920x1080. Why is that? Obviously TS container does no good for streaming,copying,pushing back to TiVo without transcoding.

[Dan203]

Not true. There are actually 3 choices for MP4 files. MP4 iPod, MP4 PSP and MP4 Generic. The generic one allows video all the way up to 1920x1080 just like TS. The other two are special cases we created because iPods and PSPs have very specific encoding and muxing requirements and we didn't want to force users to set a bunch of options manually.

One thing we did overlook is the inclusion of a generic MP4 profile in the default set. That's something I'll bring up with DanR for future releases. However for now you can create your own. Simply go to Tools->Edit profiles list... Here you can create new profiles, remove them, change their order, etc... To create a generic MP4 profile simply click New, set the encoding type to H.264 and set the file type to MP4 (Generic). If you want to make everything output with this profile a specific resolution/bitrate then set it as a Force Recode profile and set all the options accordingly. If you want to make it a profile which leaves as much as possible the same as the source then make it an Intelligent profile.*

Dan

* Bonus tip: If you want control over what bitrate is used when source is MPEG-2 and absolutely has to be recoded then you can click the Advanced Options button and adjust them in there. (these settings are adjusted per profile, so any changes you make will only apply to this particular profile)

[moyekj]

Gotcha, thanks. I hadn't seen that way of editing profiles. I was starting from copy of existing MP4 profiles from "Save As..." button.

Yes with generic MP4/H.264 I'm much happier with the options there.

BTW: I love the fact that the MOOV atom is placed at front of file for these MP4 encodes so great job on that front.

One more question if you please. Is there a way to control how many processors are used during encoding in a multi-core system? Thanks very much for your responses.

[DanR]

Is there a way to control how many processors are used during encoding in a multi-core system?

For MPEG2 encoding, there's a hidden option for one or three cores. For H264 it will use all available cores on one processor. So if you have a quad core it will use 4 cores for the encoder, don't forget there is decoding and muxing going on as well. If you actually have multiple physical processors, then the H264 encoding will be limited to the cores on one CPU.