Audio format options

Moderator: Ken Berry

Post Reply
Sainthouse

Audio format options

Post by Sainthouse »

As an enthusiastic amateur, I have been using VS 8 with great success for the past 2 years and have just upgraded to 10+. Apart from a few minor gliches, which I expect will be ironed out with patches at some point in the future, I am really enjoying the added levels of sophistication in this version.

I have to admit, though, that I have never really got to grips with the audio formats on offer for capture and rendering. Most of the video I capture is from a DV camera via i-link. In trying to work this out for myself, I stumbled across a post on this board which mentioned audio settings for DV cameras, specifically that 16 bit was the correct setting for eventual output to DVD. My camera has the choice of 12 or 16 bit, the default being 12. Should I change this for future filming?

I have found that I get the best results by capturing in DV/AVI then converting to MPEG at the 'Create Video File' stage. I am always careful to ensure all settings match, but I don't really understand which audio format I should be using! Now with 10+, not only do I have the choice of MPEG and LPCM audio, I now have Dolby Digital as well!

I am hoping that one of the real experts out there can give me some tips. I can honestly say that I haven't been unhappy with the sound quality I have achieved so far, but I would really like to understand the options, and it is one area that the User's Guide and tutorials do not seem to cover.

Thanks in anticipation

Judith
sjj1805
Posts: 14419
Joined: Wed Jan 26, 2005 7:20 am
operating_system: Windows XP Pro
System_Drive: C
32bit or 64bit: 32 Bit
motherboard: Equium P200-178
processor: Intel Pentium Dual-Core Processor T2080
ram: 2 GB
Video Card: Intel 945 Express
sound_card: Intel GMA 950
Hard_Drive_Capacity: 1160 GB
Location: Birmingham UK

Post by sjj1805 »

Pehaps someone else can address the 12/16 bit issue but regarding the other matters you brought up.

Please view
http://phpbb.ulead.com.tw/EN/viewtopic.php?t=14140
and also
http://phpbb.ulead.com.tw/EN/viewtopic.php?t=13421
User avatar
Ken Berry
Site Admin
Posts: 21429
Joined: Fri Dec 10, 2004 9:36 pm
operating_system: Windows 10
System_Drive: C
32bit or 64bit: 64 Bit
motherboard: Intel NUC7i7BNB J31145-306
processor: Core i7-7567U + 32 GB Optane
ram: 16 GB
Video Card: Intel Iris Plus 650
sound_card: Realtek High Definition Audio
Hard_Drive_Capacity: 2TB
Monitor/Display Make & Model: Kogan 32" 4K 3840 x 2160
Corel programs: VS 2020; PSP 2020; MS3D; ASP 3; DRAW 17
Location: Levin, New Zealand

Post by Ken Berry »

It is fairly normal for digital video cameras to default to 12 bit audio. However, unless you plan to do some multi-track recording on the camera using a fairly sophisticated external microphone attached to the camera, or else you plan to do some extra channel dubbing direct to the camera, I would suggest you change the camera default to 16 bit.

As the simple difference in numbers imply, in general terms 16 bit is higher quality than 12 bit. The latter samples at 32KHz but does so in 4 tracks. 16 bit, however, samples at a higher quality 48 KHZ but only uses two stereo tracks. The value in using 12 bits' extra tracks for direct dubbing to the camera, has these days been largely overtaken by the abundance of (relatively) cheap video editing programs (like VS) which can be easily used to add extra audio tracks, like background music and voiceovers. (Some of the more sophisticated, and expensive, editing programs, of course give you a huge number of possible video and audio tracks you can add.) So in effect, with these programs, you don't need the extra direct dubbing ability of 12 bit. Setting the camera to 16 bit will thus give you improved quality audio, and you can still use your software to add extra audio tracks if necessary.

By the way, you can still use an external microphone, whether your camera is set to 12 bit or 16 bit.
Ken Berry
Sainthouse

Post by Sainthouse »

Thanks for such a prompt reply, but I'm afraid it's all still as clear as mud to me! If I capture from DV tape, what is the audio format of my captured footage? Can I opt for a different format, eg Dolby Digital, in my project preferences at the edit stage and then video file settings in 'share'? What are the advantages/disadvantages of one format over another?

Sorry to ask what are probably very basic questions. Until now I have been turning a blind eye to these issues and opting for MPEG audio when given a choice, but I don't know if this is the right thing to do, especially as 10+ gives me the option of Dolby.

Thanks again

Judith
Sainthouse

Post by Sainthouse »

Ken

I was replying to sjj1805's post at the same time you were explaining about 16 v 12 bit! Thanks for your very clear explanation. I'll change my camera setting right now!

Judith
DVDDoug
Moderator
Posts: 2714
Joined: Sun Jan 23, 2005 12:50 am
Location: Silicon Valley

Post by DVDDoug »

The 16 bit, 48kHz setting is best. At that setting, the DV audio "data" is identical to LPCM audio on a DVD.

If your DV camera can record 4-channels, then you have to use 12-bit, 32kHz when recording 4 channels, because the DV spec doesn't allow 4 channels of 16 bit audio.

You can see that the bitrate requirements are the same (1536kbps) for (16 x 48k x 2) and (12 x 32k x 4). You're writing the same amount of data on the tape with 2 or 4 channels.
[size=92][i]Head over heels,
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
User avatar
Ken Berry
Site Admin
Posts: 21429
Joined: Fri Dec 10, 2004 9:36 pm
operating_system: Windows 10
System_Drive: C
32bit or 64bit: 64 Bit
motherboard: Intel NUC7i7BNB J31145-306
processor: Core i7-7567U + 32 GB Optane
ram: 16 GB
Video Card: Intel Iris Plus 650
sound_card: Realtek High Definition Audio
Hard_Drive_Capacity: 2TB
Monitor/Display Make & Model: Kogan 32" 4K 3840 x 2160
Corel programs: VS 2020; PSP 2020; MS3D; ASP 3; DRAW 17
Location: Levin, New Zealand

Post by Ken Berry »

Glad to help. Just to clarify on a couple of points in your latest post. On capture, you capture audio at the setting of the camera. If the camera is set to 12 bit, then you capture 12 bit.

As for the differences between the audio formats, I hope the first of Steve's cross-references will explain that. Briefly put, though, LPCM is to audio what DV, or uncompressed AVI to be more accurate, is to video. LPCM is high quality, uncompressed audio. As such, it creates fairly large audio files. Both NTSC and PAL players can always play LPCM audio, however, so you are always safe using it on your home-made DVDs. The size of its files may become an issue if you are also trying to squeeze as much video as possible on to one disc and can't quite make it.

Mpeg layer 2 audio is a compressed audio format which, as such, produces much smaller files, though still with extremely good quality. It is part of the PAL DVD standard, but not the NTSC standard. In theory, this means if you live in an NTSC country, not all stand-alone NTSC DVD players will necessarily play it. In practice, however, most do. With Video Studio, quite a number of people have reported problems when editing mpeg-2 video, including when it uses mpeg layer 2 audio. That was with earlier versions of VS, though the problems seemed to have diminished with VS9 and, so far, (touch wood), appear not to have resurfaced with VS10.

Then there is Dolby, which is part of both NTSC and PAL DVD standards, so you can happily use that if it is available in your video editor as a choice. It produces files about the same size as mpeg audio, and is also excellent quality. I personally would recommend that people use this instead of mpeg audio where they have the choice. The Dolby AC-3 can be either two channel stereo or, now, with VS10, 5.1 channel surround sound -- though most of us are still coming to terms with that one.

Essentially, if you are capturing DV, you will be capturing your audio in PCM format (identical to LPCM to all intents and purposes). But yes, after doing your edits, and when you are producing your DVD-compatible mpeg-2 file, you can select another audio format. As I say, I recommend Dolby, but you can also try mpeg audio. Then when you open the burning module, you make sure that the burning template you are using is set to have the same audio format (and other properties) of your mpeg-2.
Ken Berry
DVDDoug
Moderator
Posts: 2714
Joined: Sun Jan 23, 2005 12:50 am
Location: Silicon Valley

Post by DVDDoug »

LPCM is "pure". It is uncompressed and can give you the highest quality. Because it's uncompressed, it eats-up lots of space on the DVD, leaving less room for video. (And, you can't put more than 2 channels of LPCM on a DVD.*)

MPEG and Dolby AC3 are both compressed. This leaves more room on the DVD for video. You can put more hours of audio/video on a DVD with MPEG or AC3, or you can use a higher video-bitrate for higher video-quality. For that reason, I almost always use AC3.

If you live in the USA, MPEG audio is non-standard, and some players won't play it. All NTSC DVD players are required to play both LPCM and AC3.

PAL players are required to play all 3 formats, MPEG, AC3, and LPCM.

The only standard-compliant way to put 5.1 channel surround on a DVD is with AC3. You will notice that all commercial DVDs with 5.1 channel DTS audio also have an LPCM or AC3 soundtrack, because some players can't play DTS.

* You can make a 2-channel encoded "Dolby Surround" LPCM soundtrack if you have the right software... But, that's not the same as true 5.1 channel digital surround.
[size=92][i]Head over heels,
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
Sainthouse

Post by Sainthouse »

Ken, you are a star! Thank you so much for taking the time to explain this to me. I have been selecting MPEG audio and have been very happy with the results; as I am in the UK I was, unwittingly, choosing the best format for my needs. But it had always niggled me that there were other options that I didn't understand, which might have given me even better results.

Thanks once again, and many thanks to all who have posted on this topic.

Judith
Post Reply