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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I am looking into fixed-point code of the CELT decoder for real-time application. Here are some questions..<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>[1] array, window[]<o:p></o:p></b></p><p class=MsoNormal>The array, window[] is being initialized from a function below in modes.c. This array is being initialized differently for the decoder, depending on frame size and sampling freq. of the bitstream ..<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Could you provide us with fixed-point code for initialization of this array? Or you may kindly provide us with ROM tables of the array for each possible combination of frame size and sampling freq…?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>{<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>….<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>….<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>#ifndef FIXED_POINT<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'> for (i=0;i<mode->overlap;i++)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'> window[i] = Q15ONE*sin(.5*M_PI* sin(.5*M_PI*(i+.5)/mode->overlap) * sin(.5*M_PI*(i+.5)/mode->overlap));<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>#else<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'> for (i=0;i<mode->overlap;i++)<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:9.0pt;font-family:"Courier New";color:#984806'> window[i] = MIN32(32767,floor(.5+32768.*</span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:red'>sin</span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:#984806'>(.5*M_PI* </span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:red'>sin</span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:#984806'>(.5*M_PI*(i+.5)/mode->overlap) * </span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:red'>sin</span></b><b><span style='font-size:9.0pt;font-family:"Courier New";color:#984806'>(.5*M_PI*(i+.5)/mode->overlap))));<o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New"'>#endif<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>…..<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>…..<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Courier New";color:#1F497D'>}<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>[2] Usage on global stack memory<o:p></o:p></b></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In “arch.h”, there is a definition on the following constant for global processing memory (stack RAM).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New";color:green'>#define GLOBAL_STACK_SIZE 100000</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Then, dynamic RAM is allocated through calloc (<span style='font-size:10.0pt;font-family:"Courier New";color:green'>GLOBAL_STACK_SIZE, 1</span>), which means that 100,000 bytes of RAM is being allocated for decoder processing. Do we really need 100KB RAM for decoder processing (whatever called … processing RAM or stack RAM)?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>What’s peak R/W RAM requirement of the CELT decoder?<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Peak state memory (static RAM) size?<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Peak processing RAM size including local stack RAM (100,000 bytes?)?<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Minimum input bit-stream buffer size with maximum bit-rate per frame considered at 48KHz sampling rate?<o:p></o:p></p><p class=MsoListParagraph> (for example, in AAC, 1536 bytes of input bitstream buffer needed for a frame of decoding since 576kbps is the highest bit-rate in stereo channel at 48KHz sampling rate)?<o:p></o:p></p><p class=MsoListParagraph><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers,<o:p></o:p></p><p class=MsoNormal>//JB Hong<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoPlainText>_______________________________________________<o:p></o:p></p><p class=MsoPlainText>celt-dev mailing list<o:p></o:p></p><p class=MsoPlainText><a href="mailto:celt-dev@xiph.org">celt-dev@xiph.org</a><o:p></o:p></p><p class=MsoPlainText><a href="http://lists.xiph.org/mailman/listinfo/celt-dev">http://lists.xiph.org/mailman/listinfo/celt-dev</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>