diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/design/resampling.tex | 21 | ||||
| -rw-r--r-- | doc/mainpage.txt | 10 |
2 files changed, 24 insertions, 7 deletions
diff --git a/doc/design/resampling.tex b/doc/design/resampling.tex index 44aeee9b1..cf9cfb1ed 100644 --- a/doc/design/resampling.tex +++ b/doc/design/resampling.tex @@ -1,4 +1,5 @@ \documentclass{article} +\usepackage{amsmath} \begin{document} Here is what resampling we need to do. Content video is at $C_V$ fps, audio at $C_A$. @@ -18,6 +19,7 @@ $C_V$ is a DCI rate, $C_A$ is not. e.g.\ if $C_V = 24$, $C_A = 44.1\times{}10^3 \textbf{Resample $C_A$ to the DCI rate.} \section{Hard case 1} +\label{sec:hard1} $C_V$ is not a DCI rate, $C_A$ is, e.g.\ if $C_V = 25$, $C_A = 48\times{}10^3$. We will run the video at a nearby DCI rate $F_V$, @@ -31,5 +33,24 @@ resample audio to $25 * 48\times{}10^3 / 24 = 50\times{}10^3$. \medskip \textbf{Resample $C_A$ to $C_V C_A / F_V$} +\section{Hard case 2} + +Neither $C_V$ nor $C_A$ is not a DCI rate, e.g.\ if $C_V = 25$, $C_A = +44.1\times{}10^3$. We will run the video at a nearby DCI rate $F_V$, +meaning that it will run faster or slower than it should. We first +resample the audio to a DCI rate $F_A$, then perform as with +Section~\ref{sec:hard1} above. + +\medskip +\textbf{Resample $C_A$ to $C_V F_A / F_V$} + + +\section{The general case} + +Given a DCP running at $F_V$ and $F_A$ and a piece of content at $C_V$ +and $C_A$, resample the audio to $R_A$ where +\begin{align*} +R_A &= \frac{C_V F_A}{F_V} +\end{align*} \end{document} diff --git a/doc/mainpage.txt b/doc/mainpage.txt index 649c9c609..a1cd9bac8 100644 --- a/doc/mainpage.txt +++ b/doc/mainpage.txt @@ -1,7 +1,7 @@ /** @mainpage DCP-o-matic * * DCP-o-matic is a tool to create digital cinema packages (DCPs) from - * video files, or from sets of TIFF image files. It is written in C++ + * video files, or from sets of image files. It is written in C++ * and distributed under the GPL. * * Video files are decoded using FFmpeg (http://ffmpeg.org), so any video @@ -26,12 +26,8 @@ * for debugging purposes. * * Thanks are due to the authors and communities of all DCP-o-matic's dependencies. - * - * DCP-o-matic is distributed in the hope that there are still cinemas with projectionists - * who might want to use it. As Mark Kermode says, "if it doesn't have a projectionist - * it's not a cinema - it's a sweetshop with a video-screen." * - * Email correspondance is welcome to cth@carlh.net + * Email correspondance is welcome to carl@dcpomatic.com * - * More details can be found at http://carlh.net/software/dcpomatic + * More details can be found at http://dcpomatic.com/ */ |