tag:blogger.com,1999:blog-29989182883940256972024-03-13T22:00:02.213-07:00Speech Codecs: Pros & ConsThis Speech Codecs blog explain about various Speech codecs with their pros & consIPSupermarkethttp://www.blogger.com/profile/08940405702382163444noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-2998918288394025697.post-57255422908166382982009-04-29T03:13:00.000-07:002009-04-29T03:31:01.128-07:00IPsupermarket is listed on Global Semiconductor Alliance WebSite<p> </p><span style=";font-family:georgia;font-size:100%;" >GSA decision to list the IPsupermarket website on their resource page will increase the traffic & alliance of both the GSAGlobal & IPsupermarket.</span><span style="font-family:georgia;">This partnership creates marketing synergies for both the companies to target the wide need for IPs in numerous application types.</span><o:p></o:p><br /><p><br /></p><p class="MsoNormal" style="font-family:georgia;"><span style="font-size:100%;">GSA listed the IPSupermarket in their reference material of the IP catalog resources. IPsuper</span><span style="font-size:100%;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://www.gsaglobal.org/resources/ipcatalog/index.asp"><img style="margin: 0pt 10px 10px 0pt; float: left; cursor: pointer; width: 108px; height: 98px;" src="http://3.bp.blogspot.com/_q3oEoWPVdDg/SfgpDG9kywI/AAAAAAAAACk/2FdceO46dyM/s400/gsa_logo_int.gif" alt="" id="BLOGGER_PHOTO_ID_5330055292378204930" border="0" /></a></span><span style="font-size:100%;">market IP catalog provides GSA members with direct access to IPsupermarket's comprehensive catalog of Software IP & IP core, which serves as a valuable resource for SOC designers, Design House, Semicon & Services Companies, OEM and Freelancers.</span><br /></p><p></p><br /><p class="MsoNormal" style="font-family:georgia;"><span style="font-size:100%;">IPSupermarket is offering <strong>free</strong> <strong><span style="">membership for the Buyers who are looking about the information on IPs and also </span></strong>offering Free Membership to the sellers who are looking to sell their IPs.<br /><o:p> </o:p><br /></span><br /><span style=";font-family:georgia;font-size:100%;" >For more information about the GSA Listing please visit at: </span><span style=";font-family:georgia;font-size:100%;" ><a href="http://www.gsaglobal.org/resources/ipcatalog/index.asp"><span style=""><span style="">http://www.gsaglobal.org/resources/ipcatalog/index.asp</span></span></a></span><span style="font-family:georgia;font-size:100%;" > or Browse </span><a href="http://www.ipsupermarket.com/"><span style="">www.ipsupermarket.com</span></a><br /></p><p> </p>IPSupermarkethttp://www.blogger.com/profile/08940405702382163444noreply@blogger.com0tag:blogger.com,1999:blog-2998918288394025697.post-77835569602361698292009-01-09T04:32:00.000-08:002009-02-16T22:11:22.579-08:00Understanding Various Speech Codecs<div class="snap_preview"><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >The <strong>Speech codecs</strong> is a method of compression/decompression of audio file containing speech data or streaming speech format. The codecs stands for Coders / Decoders. </span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >There are various kinds of speech codecs available. Since these codecs have been implemented on different algorithms; they have different specification and application in various fields. These speech codecs generally complies Industry standards like ITU.</span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >The various software speech codecs are:</span></p><ul type="disc"><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">G.711</span></strong></li><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">G.722</span></strong></li><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">G.723 & G.723.1</span></strong></li><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">G.726</span></strong></li><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">G.728</span></strong></li><li class="MsoNormal"><strong><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >G.729</span></strong></li><li class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">AMR, AMR-WB, AMR-NB</span></strong></li></ul><h2 style="TEXT-ALIGN: justify"><span style="FONT-WEIGHT: normal"><span style="font-size:85%;"><span style="font-family:verdana;">These various </span><a href="http://www.ipsupermarket.com/viewpage/speech_codecs.html"><span style="font-family:verdana;">Speech codecs</span></a><span style="font-family:verdana;"> are technically differentiated from each other based on various factors which includes compression technology / algorithm, platform supported, bandwidth, data rates etc</span></span></span></h2><h2 style="TEXT-ALIGN: justify"><span style="FONT-WEIGHT: normal"><span style="font-size:85%;"><br /><span style="font-family:verdana;">One can easily compare & find out various Speech codecs on </span><a href="http://en.wikipedia.org/wiki/Category:Speech_codecs" target="_blank"><span style="font-family:verdana;">wikipedia.</span></a><span style="font-family:verdana;"> But still there is confusion which speech codec is the appropriate and where? However it also depends on application. But understanding pros & cons of some of these codecs gives us the better information and insight depth.</span></span></span></h2><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G.711</span></h3><p class="MsoNormal" style="TEXT-ALIGN: justify"><strong><span style="font-family:verdana;font-size:85%;">Overview</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-family:verdana;font-size:85%;">G.711 is a Pulse code modulation (PCM) of voice frequencies on a 64 kbps channel. G.711 uses a sampling rate of 8,000 samples per second. Non-uniform quantization with 8 bits is used to represent each sample, resulting in a 64 kbit/s bit rate.</span></p><p class="MsoNormal"><span style="font-family:verdana;font-size:85%;">There are two types of standard compression algorithms are used. (1) µ-law algorithm (2) A-law algorithm. </span></p><p class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Pros</strong> </span></span></p><ul type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Designed to deliver precise transmission of speech</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Very low processing overheads</span></li></ul><p class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Cons</strong> </span></span></p><ul type="disc"><li class="MsoNormal"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >Poor network efficiency</span></li><li class="MsoNormal"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >Lacks missing packet interpolation</span></li><li class="MsoNormal"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" >Including overheads, uses >64kbps, thus at least 128kbps bandwidth in each direction is required</span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Other Version</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.711.1</strong> is an extension version of G.711, G.711.1, allows the addition of narrowband and/or wideband (16000 samples/s) enhancements, which leading to data rates of 64, 80 or 96 kbit/s.</span></span></p><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G.722</span></h3><h3><span style="font-family:verdana;font-size:85%;">Overview </span></h3><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-family:verdana;font-size:85%;">G.722 is a ITU standard wideband speech codec operating at 48-64 kbit/s. Technology of the codec is based on split band ADPCM.</span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><strong><span style="font-family:verdana;font-size:85%;">Pros </span></strong></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">It is useful in fixed network voice over IP applications, where the required bandwidth is typically not prohibitive</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">It also offers a significant improvement in speech quality over older narrowband codecs such as G.711</span></li></ul><p class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Cons</strong><strong> </strong></span></span></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">They are not optimum for broadcast remotes</span></li></ul><p><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Other Version</strong><strong> </strong></span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.722.1</strong> is an ITU-T standard audio codec used for high quality speech G.722.1 is a transform-based compressor that is optimized for both speech and music. The computational complexity is quite low and the algorithmic delay end-to-end is 40 ms.</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.722.2 </strong>is also referred as AMR-WB. It is a speech coding standard developed after the AMR using same technology like ACELP. Kindly check AMR-WB for further details.</span></span></p><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G.723 & G.723.1</span></h3><p class="MsoNormal" style="TEXT-ALIGN: justify"><strong><span style="font-family:verdana;font-size:85%;">G.723 is completely different than G.723.1</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><strong><span style="COLOR: rgb(0,0,128);font-family:verdana;font-size:85%;" >G.723 Overview:</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-family:verdana;font-size:85%;">G.723 is an ITU standard for speech codecs that uses the ADPCM method and provides good quality audio at 24 and 40 Kbps.</span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Note:</strong> G.723 codec mainly used for digital circuit multiplication equipment (DCME) applications. And latter folded into <strong>G.726. </strong>Kindly see the G.726</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="COLOR: rgb(0,0,128)"><strong><span style="font-family:verdana;font-size:85%;">G.723.1 Overview:</span></strong></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.723.1</strong> is a speech codec that compresses voice audio in 30 ms frames. An algorithmic look-ahead of 7.5 ms duration means that total algorithmic delay is 37.5 ms.</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><strong><span style="font-family:verdana;font-size:85%;">Pros </span></strong></p><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;"></span></strong></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Very high compression whilst maintaining high quality audio.</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Allows simultaneous encode & decode in software (on fast computers)</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">G.723.1 is much effective in the audio portion of videoconferencing/telephony over public telephone (POTS).</span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;"></span></strong></p><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Cons </span></strong></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Requires a lot of processor power.</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Not well-suited to music or sound effects </span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Lower quality than many other codecs at similar data rates</span></li></ul><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G.726</span></h3><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;"></span></strong></p><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Overview</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.726</strong> is an ADPCM speech codec for the transmission of voice at rates of 16, 24, 32, and 40 kbit/s.G.721 and G.723 had been folded into G.726.</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Pros</strong> </span></span></p><ul type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Uses 32 Kbits which is half the rate of G.711 codec and hence increasing the usable network capacity by 100%</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Very much used on international trunks in the phone network.</span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Cons </span></strong></p><ul type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Not well-suited to music or sound effects</span></li></ul><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G.728</span></h3><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;"></span></strong></p><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Overview</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-family:verdana;font-size:85%;">G.728 uses Low-Delay Code Excited Linear Prediction (LD-CELP) compression technology at 16 kbps</span></p><p class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Pros</strong><tt> </tt></span></span></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">G.728 <tt>rates as “toll quality”. So v</tt>oice quality is really good as compared to its previous speech codecs.</span></li><li class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><tt>G.728 is a Low delay speech coder hence </tt>including satellite, cellular, and video conferencing systems</span></span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Cons </span></strong></p><ul type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Few bits are available for error protection</span></li></ul><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >G729</span></h3><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Overview</span></strong></p><p class="MsoNormal"><span style="font-family:verdana;font-size:85%;">The G.729 speech codec uses a audio data compression algorithm and compress the data at bit rates that vary between 6.4 and 12.4 kbps<br /></span></p><p class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Pros</strong> </span></span></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;">Low delay for compression of speech data as low as 10 milliseconds. Hence music or tones such as DTMF or fax tones cannot be transported reliably with this codec<strong> </strong></span></span></li><li class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;">Because of its lower bandwidth around 8 kbps it mostly used in Voice over IP (VoIP) applications for its low bandwidth requirement<strong></strong></span></span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Cons </span></strong></p><ul type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">Speech quality decreases by marginally.</span></li><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">License required for use</span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Other Version</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>G.729A/G.729B</strong> uses Conjugate-Structure Algebraic-Code-Excited Linear Prediction (CS-ACELP) compression algorithm. The reduction in complexity may result in a small decrease in voice quality. G.729A is suitable for VoIP or similar applications using multimedia, voice, and/or data</span></span></p><div class="MsoNormal" style="TEXT-ALIGN: center"><span style="COLOR: rgb(0,0,0);font-family:verdana;font-size:85%;" ><hr size="2"></span></div><h3><span style="COLOR: rgb(0,0,255);font-family:verdana;font-size:85%;" >AMR</span></h3><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Overview</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Adaptive Multi-Rate (AMR)</strong> is an audio data compression scheme optimized for speech coding. AMR was adopted as the standard speech codec by 3GPP</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>Pros</strong> </span></span></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-size:85%;"><span style="font-family:verdana;">Superior sound quality due to wider speech bandwidth<strong> </strong></span></span></li></ul><p class="MsoNormal"><strong><span style="font-family:verdana;font-size:85%;">Cons </span></strong></p><ul style="MARGIN-TOP: 0pt" type="disc"><li class="MsoNormal"><span style="font-family:verdana;font-size:85%;">The disadvantage is course the delay it introduces in the voice path.</span></li></ul><p class="MsoNormal"><strong><span style="COLOR: rgb(35,31,32);font-family:verdana;font-size:85%;" >Other Version</span></strong></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>AMR-WB </strong>(Adaptive Multi Rate WideBand<strong>)</strong> is a speech coding standard developed after the AMR using same technology like ACELP.</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-size:85%;"><span style="font-family:verdana;"><strong>AMR-NB</strong> (Adaptive Multi-Rate Narrowband) is a speech codec employed in low-bitrate applications like mobile phones. It is a form of ACELP.</span></span></p><p class="MsoNormal" style="TEXT-ALIGN: justify"><span style="font-family:verdana;font-size:85%;">To commercialize these speech codecs couples of portals are available where one can promote and procure these codecs. Such portals are design-reuse, chipestimates, </span><a href="http://www.ipsupermarket.com/"><strong><span style="font-family:verdana;font-size:85%;">IPsupermarket.com</span></strong></a><span style="font-family:verdana;font-size:85%;"> which allows you to buy/sell or license various speech codecs.</span></p></div>IPSupermarkethttp://www.blogger.com/profile/08940405702382163444noreply@blogger.com0