Dearr Hann, All, > Hi all, > > Just to inquire more about MS Stereo. I am confused about how the block is > decided between long and short blocks. > > In the previous algorithm, the blocks are decided based on LR thresholds > after L3psycho_anal. Is that true? Can't we use the final LR/MS thresholds ie > fthr for the block decision. >
Well, theoretically you could try - but so far I've never seen block decision based on final LR/MS thresholds. That is pretty much useless, because these thresholds are "imaginery" only - after final reconstruction in the decoder you'll be ending with noise in left and right channel, so it is natural to use L and R channels for block decision. You would get false 'attack' information if the last frame was L and next frame is M, because M will have higher PE - and after rematrixing this noise will be spread to both channels, and not only to the left one. > One more thing on bmax(b) from 13818-7 MS Stereo section. Is that applied to > both short and long blocks? In lame 3.21, I notice that it is use on the Yes - it is applied to both blocks if your encoder uses short block psychoacoustics. > scalefactorbands instead of the partitions. So when the standard states to > calculate the LR/MS and final thresholds, it actually means the LR/MS ratios in > the after calculating the PE. Is that right? > You must apply BMAX before M/S decision, theoretically you could apply it either on scalefactorbands or partitions - it is all your choice. In my software I apply BMAX on partitions, but in some other projects I've seen application of BMLD thresholds after computing allowed noise in each scalefactor band. Really makes no difference, except maybe in number of multiplications :) > Will appreciate all assistance. > > Hann Long > NUS Student Best Regards, ************************************************* Ivan Dimkovic, Technical Manager PsyTEL Research Multimedia Coding Solutions Belgrade Yugoslavia phone: +381 63 264 334 phone: +381 64 11 40 600 fax: +381 11 32 25 275 email: [EMAIL PROTECTED] www: http://www.psytel-research.co.yu ************************************************* This e-mail may contain confidential information which is legally privileged. The information is solely for the use of the addressee named above. If you are not the intended recipient, any disclosure, copying, distribution or other use of the contents of this information is strictly prohibited. If you have received this e-mail in error, please notify us by return e-mail and delete this message. Thank you. _______________________________________________ mp3encoder mailing list [EMAIL PROTECTED] http://minnie.tuhs.org/mailman/listinfo/mp3encoder
