TSSA Workshop Seminar: Changing Buffer Numbers

1. TSSA Workshop Seminar:Changing Buffer Numbers Prepared by Mustafa Özden 9.4.2001 Supervised by Natalia Gavrilova

2. Contents • Motivation • Introduction • Aim and Expectations • Modifications • Results • Conclusion Mustafa Özden

3. Motivation • MPEG: Motion Pictures Experts Group • MPEG-4 :the standard for multimedia for the web and mobility • TSSA: TriMedia Software Streaming Architecture • Standardized methods for collaboration of application programmers and component developers Mustafa Özden

4. Introduction Digitizer Filter Renderer Mustafa Özden

5. From Fread (Digitizer) To Fwrite (Renderer) DCT Quantizer VLCEnc Introduction From Fread (Digitizer) To Fwrite (Renderer) Frame Manager DCT Quantizer VLCEnc Inv.DCT Inv.Quant Mustafa Özden

6. Introduction • Steps: • Frame Manager is taken out. • Second output of quantizer is omitted. • Inverse Quantizing and Inverse DCT are removed. • Buffers are arranged according to component and application needs. Mustafa Özden

7. From Fread (Digitizer) To Fwrite (Renderer) DCT Quantizer VLCEnc Introduction • Resulting Application: • Consists of Fread, DCT, Quantizer and VLC Encoder components arranged as following: Mustafa Özden

8. Aim • Buffer between Quantizer and VLC Encoder • One buffer for all macroblocks in normal application. • Task: • To change the number of buffers between Quantizer and VLC Encoder and make a „comparison“ for different number of buffers. Mustafa Özden

9. Expectations FACT: • VLC Encoder is designed to have the input from one buffer • No possibility to modify the component itself to make it work with more number of buffers • Solution: Copy all buffers to one temporary buffer and make VLC Encoder to work with this temporary buffer. Mustafa Özden

10. Expectations • Expected: • No or negligible change of time in quantizer‘s processing of data. • Some more time for copying multiple buffers into one temporary buffer. • More buffers , more time to copy • Obviously no change in time for VLC Encoder data processing after copying buffers. Mustafa Özden

11. Modifications • Input file: 128x96 pixels • 48 macroblocks in total. • Initial situation: • One buffer between Quantizer and VLC Encoder for all 48 macroblocks • Tested: 6 buffers(8 macroblocks/buffer) and 48 buffers(each macroblock in a seperate buffer) Mustafa Özden

12. Possible Modification Original State Aimed Modification Buffer – 48 Macroblocks Temporary buffer of 48 macroblocks 6 buffers of 8 macroblocks 6 buffers of 8 macroblocks Modifications Quantizer VLC Encoder Mustafa Özden

13. Modifications • Second modification : • 48 buffers,each with 1 macroblock capacity. • Copied to a temporary buffer. Mustafa Özden

14. Results • Original Speed : • DCT Component Process:............... • Quantizer Component Process: ...... • VLC Encoder Process:..................... • VLC Encoder Process 2*.................. • Overall Speed: 350516 Cycles 6680214 Cycles 2657298 Cycles 428 Cycles 10023178 Cycles Mustafa Özden

15. Results • !VLC Encoder Problem in modifications!: • Process stop at a point?? • Could not be solved!! :o( • Results are taken according to the point it stops. • The rest of the process are not changed in modified applications. • Data coming to this point in all modified applications are the same!! • But still VLCEncoder does not work... Mustafa Özden

16. Results Mustafa Özden

17. Conclusion • Best choice in this case is one buffer • Important! • VLC Encoder could not be modified to accept multiple buffers • Copying to a temporary buffer takes time! • Multiple buffers between Quantizer and VLC Encoder – not advantageous • In these conditions..... Mustafa Özden

18. Thank you for your help,support and co-operation