Hi Ian, RealAudio10 is a marketing name that is applied to a family of codecs. Which codec is selected for a given stream is partly based on bitrate and target audience. The numbers you have for RealAudio8 performance still apply, as that is one of the codecs under the RA10 umbrella. The name that we give this codec in the source is "ra8lbr", which stands for RealAudio8 Low BitRate. This codec is generally used for encoding music from 8kbps to 96kbps.
In addition to the ra8lbr codec, RealAudio10 also includes AAC for encoding high bitrate audio (64kbps and above), and RealAudio Voice for encoding speech at 5 to 16kbps. AAC is the main new addition for RA10, although there is also a lossless codec. The RealNetworks codec group just released a fixed point AAC decoder that has been highly optimized for ARM. This source is publicly available in the datatype project: /datatype/aac/codec/fixpt/decoder/ The performance for this AAC implementation is given in an excel spreadsheet the docs subdirectory. Here's a link for your convenience: https://helixcommunity.org/viewcvs/cgi/viewcvs.cgi/datatype/aac/codec/fixpt/decoder/ About the backwards compatibility question... there are some really old RA codecs that are no longer in use, although there is probably some of those streams still out in the wild. To my knowledge, these are not supported anymore except by the desktop RealPlayer. Generally, if you have ra8lbr, aac, and ra-voice, you are considered to have complete support for RA10. Regards, -Hans > > Hi, > > I have some questions regarding the RealAudio 10 codec and would be > grateful for any help you can give: > > 1. What are the processor requirements for the RealAudio 10 codec as > compared to the RealAudio 8 codec? I am looking at running the codec on > an ARM7 or ARM9, I assume that I need the RealAudio 10 codec as this is > the latest codec, I have found MHz figures for the RealAudio 8 codec on > the Helix site at https://datatype.helixcommunity.org/ra8fixpt.html, I > would like to know how the RealAudio 10 codec compares. > > 2. Are RealAudio codecs backwards compatible with previous RealAudio > codecs - i.e. can the RealAudio 10 codec decode all RealAudio streams, > or do I also need a RealAudio 8 codec and other previous RealAudio > codecs? > > Thanks > > Ian Dimond > > > _______________________________________________ > Audio-dev mailing list > [email protected] > http://lists.helixcommunity.org/mailman/listinfo/audio-dev > _______________________________________________ Audio-dev mailing list [email protected] http://lists.helixcommunity.org/mailman/listinfo/audio-dev
