12 bit or 16 bit recording

[bennetts]

My Sony Digital8 camera has the option to record the audio in 12 bit or 16 bit. What is the reason for having this option and the advantage of using one over the other? All my home movies are being put on DVD (a process that has taken me just over a year and counting) using Ulead VideoStudio 8 and I don't know what effect the audio bit setting will have on the video project.

[yoda313]

Hi,

Well I don't have a dv cam but I know a thing or two about bitrates.

Put simply a higher bitrate will sound better at the cost of more space being used to accomodate it. The best possible way to determine the difference is to perform your own real world test.

Take a subject you want to video tape and use both settings. Determine which one is acceptable to you and see if there is any quality hit or space hit based on the bitrate.

kevin

[adam]

The only purpose of the 12 bit setting is because it is necessary to overdub audio through the camcorder. If you are transferring the footage to the pc you can add your own overdubs, if you even need them, so there is no reason to use anything other than 16 bit.

[daamon]

Hi bennetts,

In my experience (based on the two DV cams I own), 12 bit audio is sampled at a frequency of 32KHz whereas 16 bit audio is sampled at 48KHz.

As your DV footage is going to DVD, and DVD specs require 48KHz audio, 16 bit is the one to go for.

yoda313 has misread or misunderstood "12 bit" and "16 bit" - this has nothing to do with the bitrate of the audio as, I believe, both are recorded as LPCM (or uncompressed audio) on the DV cam, which translates to a WAV file when transferred to PC. WAV is always at 1,536kbps - irrespective of 12 bit (32KHz) or 16 bit (48KHz).

[edDV]

See this thread and ask any additional questions.

https://www.videohelp.com/forum/viewtopic.php?t=265201&highlight=12bit

[bennetts]

Thanks for your quick help. I have set the camera now at 16 bit and go from there.

[yoda313]

Hi,

yoda313 has misread or misunderstood "12 bit" and "16 bit" - this has nothing to do with the bitrate of the audio as, I believe, both are recorded as LPCM (or uncompressed audio) on the DV cam, which translates to a WAV file when transferred to PC. WAV is always at 1,536kbps - irrespective of 12 bit (32KHz) or 16 bit (48KHz).

Sorry. As I said I don't have a dv cam. I was just trying to offer advice based on basic video information.

Kevin

[turk690]

LPCM/WAV bitrate is 1536kb/s ONLY when the sampling rate is 48KHz and the quantization is 16bit (16bits x 48000Hz x 2, the 2 is for 2-channel). A 12bit, 32KHz, 2-ch WAV file will have a bitrate of 768kb/s (12 x 32000 x 2). These specs were chosen for DV so that two of the latter can fit in the space occupied by one of the former (choosing 12bit setting in the audio in a DV/D8 camcorder affords TWO 2-ch pairs, as against only one for the 16bit setting). Incidentally, CDDA bitrate is 1411.2kb/s (16 x 44100 x 2).

[daamon]

Hmmm.... Interesting turk690 - Thanks for the info. Seems I should stand corrected and that yoda313 was closer to the truth than I gave him credit for. My apologies yoda...

That then begs the question "What is quantization?" - but that's some research for me.

[kosekjm]

I don't know about the differences between the formats, and it seems like that's already been discussed, but watch the Ulead software. I have Ulead VS8 and Movie Factory 3.0 and have seen issues with 12bit vs 16bit.

I have a camera that offers both 12bit and 16bit mode. I had originally taped most of my videos in 12bit mode with the thought of dubbing over later. I never bothered, because I found it to be easier to do that during the DVD creation, so I switched the camera back to 16bit mode. When I then went to capture that tape (Half of the video was at 12bit and the other half was at 16bit), the programs (Both VS8 and MF3) "got confused". In the second half of the capture, the audio was horridly out of sync. It appeared, to me at least, that the Ulead software would continue the capture at the bit rate that it had detected during the initial startup of the capturing. Now if I stopped the capture at the switch point and then restarted a new capture at the 16bit area, then the audio was fine. I was then able to add the clips and author the dvd with no audio problems. This only happened on the tape that had mixed audio rates. The tapes that I captured that had the same rate (whether it was 12 or 16bit) all transferred with no audio issues.

I don't know if this is common to all capture programs, or just these ones, as these are the only ones that I have played with. They work for me for what I want, as long as I watch for mixed mode tapes. Figured I pass that along.

[Gew]

Okey guys, I know I'm bumping a +5 year old thread, but the topic was of great match and I also found very good information in this thread. Especially turk690's briefing was of great interest.

LPCM/WAV bitrate is 1536kb/s ONLY when the sampling rate is 48KHz and the quantization is 16bit (16bits x 48000Hz x 2, the 2 is for 2-channel). A 12bit, 32KHz, 2-ch WAV file will have a bitrate of 768kb/s (12 x 32000 x 2). These specs were chosen for DV so that two of the latter can fit in the space occupied by one of the former (choosing 12bit setting in the audio in a DV/D8 camcorder affords TWO 2-ch pairs, as against only one for the 16bit setting). Incidentally, CDDA bitrate is 1411.2kb/s (16 x 44100 x 2).

Makes perfectly good sense. Not until now I have realized the mathematical relationship between bits/bitrate/samplerate. Good to know, indeed so. Anyways. Like I said, I was considering starting a new thread for my little question, but since this one felt so "right on spot" I couldn't help bumping, hope no one disapproves. Anyways, here's my thing..

I have a Sony Handycam DCR-HC53E. I've always had 32KHz audio when capping from tape to PC. It hasn't bothered me. Well at first I thought it was some setting in WinDV, but later on I decided that it was probably just so that my camera was limited to 32KHz. But so today, I found a setting "Audio mode", where I could check 12-bit or 16-bit. I changed it to 16-bit, and shot a couple of seconds for tests. Started WinDV and capped. Amazing, MediaInfo now reports my DV-AVI clips with 48KHz audio. Just marvelous!

Now, here's the thing... MediaInfo seems to report 12-bit caps aswell as 16-bit caps as 16-bit. Hence, the approximation that turk690 came up with don't match my fooage. I.e. it should be 12x32x2=768kbps, but it's reported as 16-bit, but 32KHz, hence bitrate is 1024kbps.

This is the kind of trifle slash little thing that keeps my awake at night. Wondering, why's that? Any clues? I've done some Google research, and some article suggested that 12-bit audio is really no standard, so that what is 12-bit worth of audio is really defined as 16 bits, whereas 4 bits is made of some sort of padding/zerobits. Could this be the answer?


Ty in adv~
Regards~

[jagabo]

Now, here's the thing... MediaInfo seems to report 12-bit caps aswell as 16-bit caps as 16-bit. Hence, the approximation that turk690 came up with don't match my fooage. I.e. it should be 12x32x2=768kbps, but it's reported as 16-bit, but 32KHz, hence bitrate is 1024kbps.

This is the kind of trifle slash little thing that keeps my awake at night. Wondering, why's that? Any clues? I've done some Google research, and some article suggested that 12-bit audio is really no standard, so that what is 12-bit worth of audio is really defined as 16 bits, whereas 4 bits is made of some sort of padding/zerobits. Could this be the answer?

Maybe it's a matter of the second audio stream in type 2 DV AVI. The DV stream (which has both video multiplexed) may have 12 bit, 32KHz audio, whereas the separate audio stream has a 16 bit 48 KHz audio. MediaInfo is reporting the separate audio stream, not the one in the DV stream. Ie, the camcorder recorded 12 bit audio but the capture program made a separate 16 bit audio stream out of it.

[edDV]

Bottom line there are only two cases where you wouldn't set a DV camcorder to 16bit 48KHz Stereo...

1. You have a prosumer DV camcorder capable of 4 channel direct recording and need four separate tracks (e.g. two wireless mics plus the stereo camcorder mic for ambient sound).

2. You have a consumer or prosumer cam and need to add a narration track or add background music by editing in the camcorder. Each DV cam has a mixer to allow a secondary audio mix to the internal camcorder mic audio.

DV transfer over IEEE-1394 only supports 2 audio channels at a time. The two channels you get depends on the mixer setting. 4 audio channel transfer requires two passes with the mixer set first to Stereo 1 then a second pass with Stereo 2.

If you already recorded 12bit 32 KHz, you are stuck. You can convert but you can't restore 16bit 48 KHz audio quality.

[Gavino]

Maybe it's a matter of the second audio stream in type 2 DV AVI. The DV stream (which has both video multiplexed) may have 12 bit, 32KHz audio, whereas the separate audio stream has a 16 bit 48 KHz audio. MediaInfo is reporting the separate audio stream, not the one in the DV stream. Ie, the camcorder recorded 12 bit audio but the capture program made a separate 16 bit audio stream out of it.

You may be right about that, but the 16 bit stream will still have a sampling rate of 32 KHz.
The data is simply padded, not resampled.