<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>the side channel bps is 1 larger than the raw bps because it's a difference between left and right channel values.<br></span></div><div><br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; margin-top: 5px; padding-left: 5px;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Eri Eri <guguieri@hotmail.com><br> <b><span style="font-weight: bold;">To:</span></b> flac-dev@xiph.org <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, September 26, 2011 1:17 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> [Flac-dev] mid-side coding
and bits per sample<br> </font> </div> <br>
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Dear list,<br><br>i'm doing a bit of analisys on flac's source code and i've run into something i can't quite grasp.<br><br>flac version 1.2.1<br><br>flaclib C<br><br>stream_encoder.c<br><br>function "process_subframes_"<br><br>line 2999<br><br>++++++++++++++++++++++<br> if(do_mid_side) {<br> FLAC__ASSERT(encoder->protected_->channels == 2);<br> for(channel = 0; channel < 2; channel++) {<br> const unsigned w = get_wasted_bits_(encoder->private_->integer_signal_mid_side[channel], encoder->protected_->blocksize);<br> encoder->private_->subframe_workspace_mid_side[channel][0].wasted_bits = encoder->private_->subframe_workspace_mid_side[channel][1].wasted_bits = w;<br>
encoder->private_->subframe_bps_mid_side[channel] = encoder->protected_->bits_per_sample - w + (channel==0? 0:1);<br> }<br> }<br>++++++++++++++++++++++++<br><br>In that piece of code the encoder determines how many wasted bits there are in each channel (mid-side) and calculates effective BPS for each of them. What i don't understand is why it should add one bit to the BPS of the side channel "(channel==0? 0:1)", eventhough there is no "correction" to wasted bits. Could someone shed light on this?<br>Thank you very much in advance!<br> </div></div>
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