116 lines
4.0 KiB
C
116 lines
4.0 KiB
C
/*
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* Frontend Status Monitor plugin for the Video Disk Recorder
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*
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* See the README file for copyright information and how to reach the author.
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*
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* AC3 Audio Header: http://www.atsc.org/standards/a_52a.pdf
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*/
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#include "femontools.h"
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#include "femonac3.h"
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#define IS_AC3_DATA(buf) (((buf)[0] == 0x0b) && ((buf)[1] == 0x77))
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static unsigned int ac3_bitrates[32] =
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{
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32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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};
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static unsigned int ac3_freq[4] =
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{
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480, 441, 320, 0
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};
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//static unsigned int ac3_frames[3][32] =
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//{
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// {64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 640, 768, 896, 1024, 1152, 1280, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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// {69, 87, 104, 121, 139, 174, 208, 243, 278, 348, 417, 487, 557, 696, 835, 975, 1114, 1253, 1393, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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// {96, 120, 144, 168, 192, 240, 288, 336, 384, 480, 576, 672, 768, 960, 1152, 1344, 1536, 1728, 1920, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
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//};
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bool getAC3AudioInfo(uint8_t *buf, int len, ac3_info_t *info)
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{
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if (!IS_AC3_DATA(buf) || (len < 8))
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return false;
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uint8_t *data = buf + 2;
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uint8_t frame = (uint8_t)(data[2] & 0x3f);
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info->bitrate = 1000 * ac3_bitrates[frame >> 1];
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uint8_t fr = (data[2] & 0xc0 ) >> 6;
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//uint8_t sz = ac3_frames[fr][frame >> 1];
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//if ((frame & 1) && (fr == 1))
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// sz++;
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//sz <<= 1;
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info->samplingFrequency = 100 * ac3_freq[fr];
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info->bitstreamMode = (data[3] & 7);
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int acm = (data[4] & 0xE0) >> 5;
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info->audioCodingMode = acm;
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if ((acm & 0x01) && (acm != 0x01)) {
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// 3 front channels
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info->centerMixLevel = (data[4] & 0x18) >> 3;
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if (acm & 0x04) {
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// a surround channel exists
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info->surroundMixLevel = (data[4] & 0x06) >> 1;
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if (acm == 0x02) {
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// if in 2/0 mode
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info->dolbySurroundMode = ((data[4] & 0x01) << 1) | ((data[5] & 0x80) >> 7);
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info->lfe = (data[5] & 0x40) >> 6;
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info->dialogLevel = (data[5] & 0x3e) >> 1;
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}
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else {
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info->dolbySurroundMode = AUDIO_DOLBY_SURROUND_MODE_INVALID;
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info->lfe = (data[4] & 0x01);
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info->dialogLevel = (data[5] & 0xF8) >> 3;
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}
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}
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else {
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info->surroundMixLevel = AUDIO_SURROUND_MIX_LEVEL_INVALID;
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if (acm == 0x02) {
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// if in 2/0 mode
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info->dolbySurroundMode = (data[4] & 0x06) >> 1;
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info->lfe = (data[4] & 0x01);
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info->dialogLevel = (data[5] & 0xF8) >> 3;
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}
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else {
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info->dolbySurroundMode = AUDIO_DOLBY_SURROUND_MODE_INVALID;
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info->lfe = (data[4] & 0x04) >> 2;
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info->dialogLevel = (data[4] & 0x03) << 3 | ((data[5] & 0xE0) >> 5);
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}
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}
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}
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else {
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info->centerMixLevel = AUDIO_CENTER_MIX_LEVEL_INVALID;
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if (acm & 0x04) {
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// a surround channel exists
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info->surroundMixLevel = (data[4] & 0x18) >> 3;
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if (acm == 0x02) {
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// if in 2/0 mode
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info->dolbySurroundMode = (data[4] & 0x06) >> 1;
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info->lfe = (data[4] & 0x01);
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info->dialogLevel = (data[5] & 0xF8) >> 3;
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}
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else {
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info->dolbySurroundMode = AUDIO_DOLBY_SURROUND_MODE_INVALID;
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info->lfe = (data[4] & 0x04) >> 2;
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info->dialogLevel = (data[4] & 0x03) << 3 | ((data[5] & 0xE0) >> 5);
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}
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}
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else {
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info->surroundMixLevel = AUDIO_SURROUND_MIX_LEVEL_INVALID;
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if (acm == 0x02) {
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// if in 2/0 mode
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info->dolbySurroundMode = (data[4] & 0x18) >> 3;
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info->lfe = (data[4] & 0x04) >> 2;
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info->dialogLevel = (data[4] & 0x03) << 3 | ((data[5] & 0xE0) >> 5);
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}
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else {
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info->dolbySurroundMode = AUDIO_DOLBY_SURROUND_MODE_INVALID;
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info->lfe = (data[4] & 0x10) >> 4;
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info->dialogLevel = ((data[4] & 0x0F) << 1) | ((data[5] & 0x80) >> 7);
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}
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}
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}
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return true;
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}
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