{"id":3079,"date":"2023-02-06T19:41:30","date_gmt":"2023-02-06T19:41:30","guid":{"rendered":"http:\/\/mclements.net\/blogWP\/?p=3079"},"modified":"2023-02-08T18:38:51","modified_gmt":"2023-02-08T18:38:51","slug":"audio-how-much-data-is-that","status":"publish","type":"post","link":"http:\/\/mclements.net\/blogWP\/index.php\/2023\/02\/06\/audio-how-much-data-is-that\/","title":{"rendered":"Audio: How Much Data is That?"},"content":{"rendered":"

It’s easy to compute but I figured I’d save it here for reference<\/p>\n\n\n\n\n\n\n\n\n\n\n
Rate<\/strong><\/td>bPS<\/strong><\/td>BPS<\/strong><\/td>KB\/sec<\/strong><\/td>Mins\/GB<\/strong><\/td>CD ratio<\/strong><\/td>Notes<\/strong><\/td><\/tr>\n
44.1-16<\/td>1,411,200<\/td>176,400<\/td>172.27<\/td>101<\/td>1.00<\/td>Redbook CD<\/td><\/tr>\n
44.1-24<\/td>2,116,800<\/td>264,600<\/td>258.4<\/td>67<\/td>1.50<\/td><\/tr>\n
48-16<\/td>1,536,000<\/td>192,000<\/td>187.5<\/td>93<\/td>1.09<\/td><\/tr>\n
48-24<\/td>2,304,000<\/td>288,000<\/td>281.25<\/td>62<\/td>1.63<\/td>Standard DVD<\/td><\/tr>\n
88.2-24<\/td>4,233,600<\/td>529,200<\/td>516.80<\/td>33<\/td>3.00<\/td><\/tr>\n
96-24<\/td>4,608,000<\/td>576,000<\/td>562.5<\/td>31<\/td>3.27<\/td>Popular for modern classical music recordings<\/td><\/tr>\n
176.4-24<\/td>8,467,200<\/td>1,058,400<\/td>1,033.6<\/td>16.9<\/td>6.00<\/td><\/tr>\n
192-24<\/td>9,216,000<\/td>1,152,000<\/td>1,125.0<\/td>15.5<\/td>6.53<\/td><\/tr>\n<\/table>\n\n

This represents actual data bits to represent the music – no overhead. If you want to know what bandwidth is needed to carry an SPDIF signal at a given rate, add extra for packet overhead.<\/p>\n

The formula is simple:<\/p>\n

bits per second = S * C * B\r\nS = sample rate (samples per second)\r\nC = channels (2 for stereo)\r\nB = bits per sample<\/pre>\n
For example for CD we have<\/p>\n
S = 44100\r\nC = 2\r\nB = 16\r\nS * C * B = 1,411,200 bits per second<\/pre>\n
Note: most DACs internally oversample before D-A conversion. They typically oversample at the highest integer multiple of the source rate that is less than their max rate. For example the Cirrus\/Wolfson WM8741 has a max rate of 192k, so CD and DVD are oversampled 4x to 176.4 and 192 respectively. This happens automatically within the DAC chip. Because of this, it’s usually pointless to oversample an audio signal before feeding it to a DAC – the DAC is going to do it anyway, so why waste processing power and bandwidth doing it yourself?<\/p>\n","protected":false},"excerpt":{"rendered":"
It’s easy to compute but I figured I’d save it here for reference This represents actual data bits to represent the music – no overhead. If you want to know what bandwidth is needed to carry an SPDIF signal at a given rate, add extra for packet overhead. The formula is simple: bits per second … Continue reading Audio: How Much Data is That?<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,17,2],"tags":[],"class_list":["post-3079","post","type-post","status-publish","format-standard","hentry","category-audio","category-math","category-tech"],"_links":{"self":[{"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/posts\/3079","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/comments?post=3079"}],"version-history":[{"count":15,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/posts\/3079\/revisions"}],"predecessor-version":[{"id":3095,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/posts\/3079\/revisions\/3095"}],"wp:attachment":[{"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/media?parent=3079"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/categories?post=3079"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/mclements.net\/blogWP\/index.php\/wp-json\/wp\/v2\/tags?post=3079"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}