| 0,0 → 1,89 |
|---|
| /* |
| mpeghead: the bits of an MPEG frame header |
| |
| copyright ?-2011 by the mpg123 project - free software under the terms of the LGPL 2.1 |
| see COPYING and AUTHORS files in distribution or http://mpg123.org |
| initially written by Michael Hipp & Thomas Orgis (from parse.c) |
| */ |
| #ifndef MPG123_MPEGHEAD_H |
| #define MPG123_MPEGHEAD_H |
| |
| /* |
| Avoid human error, let perl do the work of dissecting an MPEG header into parts. |
| To be clear: Never edit the following definitions by hand, modify the code block inside this comment and run it through perl instead! |
| |
| $head = "AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM"; |
| %parts = qw(A sync B version C layer D crc E bitrate F samplerate G padding H private I channel J chanex K copyright L original M emphasis); |
| for(sort keys %parts) |
| { |
| $name = uc($parts{$_}); |
| $bits = $head; |
| $bits =~ s/$_/1/g; |
| $bits =~ s/[^1 ]/0/g; |
| print "\/\* $bits \*\/\n"; |
| $bits =~ s/\s//g; |
| print "#define HDR_$name".(" " x (18-length($name))).sprintf("0x%08x", eval("0b$bits"))."\n"; |
| $bits =~ m/(0*)$/; |
| print "#define HDR_${name}_VAL(h)".(" " x (11-length($name)))."(((h)\&HDR_$name) >> ".length($1).")\n"; |
| } |
| */ |
| |
| /* 11111111 11100000 00000000 00000000 */ |
| #define HDR_SYNC 0xffe00000 |
| #define HDR_SYNC_VAL(h) (((h)&HDR_SYNC) >> 21) |
| /* 00000000 00011000 00000000 00000000 */ |
| #define HDR_VERSION 0x00180000 |
| #define HDR_VERSION_VAL(h) (((h)&HDR_VERSION) >> 19) |
| /* 00000000 00000110 00000000 00000000 */ |
| #define HDR_LAYER 0x00060000 |
| #define HDR_LAYER_VAL(h) (((h)&HDR_LAYER) >> 17) |
| /* 00000000 00000001 00000000 00000000 */ |
| #define HDR_CRC 0x00010000 |
| #define HDR_CRC_VAL(h) (((h)&HDR_CRC) >> 16) |
| /* 00000000 00000000 11110000 00000000 */ |
| #define HDR_BITRATE 0x0000f000 |
| #define HDR_BITRATE_VAL(h) (((h)&HDR_BITRATE) >> 12) |
| /* 00000000 00000000 00001100 00000000 */ |
| #define HDR_SAMPLERATE 0x00000c00 |
| #define HDR_SAMPLERATE_VAL(h) (((h)&HDR_SAMPLERATE) >> 10) |
| /* 00000000 00000000 00000010 00000000 */ |
| #define HDR_PADDING 0x00000200 |
| #define HDR_PADDING_VAL(h) (((h)&HDR_PADDING) >> 9) |
| /* 00000000 00000000 00000001 00000000 */ |
| #define HDR_PRIVATE 0x00000100 |
| #define HDR_PRIVATE_VAL(h) (((h)&HDR_PRIVATE) >> 8) |
| /* 00000000 00000000 00000000 11000000 */ |
| #define HDR_CHANNEL 0x000000c0 |
| #define HDR_CHANNEL_VAL(h) (((h)&HDR_CHANNEL) >> 6) |
| /* 00000000 00000000 00000000 00110000 */ |
| #define HDR_CHANEX 0x00000030 |
| #define HDR_CHANEX_VAL(h) (((h)&HDR_CHANEX) >> 4) |
| /* 00000000 00000000 00000000 00001000 */ |
| #define HDR_COPYRIGHT 0x00000008 |
| #define HDR_COPYRIGHT_VAL(h) (((h)&HDR_COPYRIGHT) >> 3) |
| /* 00000000 00000000 00000000 00000100 */ |
| #define HDR_ORIGINAL 0x00000004 |
| #define HDR_ORIGINAL_VAL(h) (((h)&HDR_ORIGINAL) >> 2) |
| /* 00000000 00000000 00000000 00000011 */ |
| #define HDR_EMPHASIS 0x00000003 |
| #define HDR_EMPHASIS_VAL(h) (((h)&HDR_EMPHASIS) >> 0) |
| |
| /* |
| A generic mask for telling if a header is somewhat valid for the current stream. |
| Meaning: Most basic info is not allowed to change. |
| Checking of channel count needs to be done, too, though. So, |
| if channel count matches, frames are decoded the same way: frame buffers and decoding |
| routines can stay the same, especially frame buffers (think spf * channels!). |
| */ |
| #define HDR_CMPMASK (HDR_SYNC|HDR_VERSION|HDR_LAYER|HDR_SAMPLERATE) |
| |
| /* A stricter mask, for matching free format headers. */ |
| #define HDR_SAMEMASK (HDR_SYNC|HDR_VERSION|HDR_LAYER|HDR_BITRATE|HDR_SAMPLERATE|HDR_CHANNEL|HDR_CHANEX) |
| |
| /* Free format headers have zero bitrate value. */ |
| #define HDR_FREE_FORMAT(head) (!(head & HDR_BITRATE)) |
| |
| /* A mask for changed sampling rate (version or rate bits). */ |
| #define HDR_SAMPMASK (HDR_VERSION|HDR_SAMPLERATE) |
| |
| #endif |