采样率转换的意识,在Pro Tools 10,第2部分

Pro Tools 10 does a lot of the sample rate conversion for you behind the scenes. However, there are times when you'll need to be sample-rate savvy. Mike Watkinson demonstrates when and why in Part 2.  

本条第1部分中,我们讨论了10 Pro Tools的能力,在同一会议不同的采样率播放音频文件,和Pro Tools的选项时提供进口音频会话。在纯音乐的情况下(也就是说,在后期制作),目的是结束播放所有的音频以同样的速度,它最初被记录。但是在后期制作中,它有时需要改变音频的速度,以应付不断变化的动态影像格式的需求,尤其是当从电影,视频或反之亦然。


上拉和下拉功能

为了应付与每个formatwhen移动图像的技术限制从电影转移到视频或视频到filmits速度要改变。这意味着需要加快或放慢,以配合音频。 Pro Tools的10提供拉或下拉的采样率,为了实现这一目标的能力。下表显示的速度变化,需要采取当传输音频从一个格式到另一个地方:

table of sample rate conversions

How Pro Tools displays the speed changes required by changing frame rate

Pro Tools中如何显示速度变化需要改变帧速率


范例 - 下拉

例如,您已提供48 kHz时,所在位置的画面在每秒24帧(fps)的捕获记录位置的声音。为了在一台电脑的画面编辑已转移到29.97(适用于NTSC广播)的视频。影片将运行慢,所以0.1%,比其原始来源(也就是一秒钟的时间码是一个实时的第二长0.1%,比)的音频需要拔下来,否则这将是太快(如果不调整进口)。

  • In Pro Tools then, set the session sample rate to 48 kHz
  • Import the location audio to the session by using the Import Audio dialog (File > Import > Import Audio or Shift-Command-i)
  • You will be offered to either ‘Add’ or ‘Copy’ the audio; choose ‘Copy’ then tick the ‘Apply SRC’ checkbox
  • From the ‘Source Sample Rate’ drop-down menu choose 48 kHz (Pull Up/Down) and then 47, 952 - 0.1% Down (Film to NTSC)

Choosing the appropriate source sample rate

选择合适的源采样率


然后把Pro Tools会会议的目标采样率的音频,如果是47952赫兹;如果是这样的话,那么48000样本超过1秒稍长播放音频将因此减缓0.1%。

由此产生的音频将48 kHz的文件,但将在与视频同步。

This image shows the effect of slowing down a 1 second file by 0.1%; note that 1 second of timecode is longer than 1 second of real time

此图像显示了1秒的文件,由0.1%放缓的影响;注1秒的时间码是长于1秒的实时


转换质量。

当您将采样率转换,这样你也有一个转换质量的选择范围从低(最快)

Sample rate conversion quality settings

采样率转换质量设置




Mike has been obsessed with music software since he first saw Fairlight's Page-R, and has tracked its development through his work as a performer, composer and producer. As a writer he has contributed articles to Sound On Sound since 1999, and currently writes their Apple Notes column. As well as being a certified Logic Pro and Pro Too... Read More

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