Another Story of PS3 (PS3 A/V articles by Masakazu Honda at PC Watch)

[one]

Masakazu Honda currently runs a mini-series articles titled "Another Story of PS3" in his regular series articles (Weekly Mobile News) at PC Watch. It reports about the audio/video capability of the PS3 by interviewing Sony developers in charge of audio/video players in the PS3. Here are some findings gleaned from them. As I'm no audio/videophile, I hope someone clarify how much they should be appreciated in the world of buffs.

The first in the series is about the SACD player.
http://pc.watch.impress.co.jp/docs/2006/1122/mobile357.htm

• Though PSX (the DVD recorder) was too weak to decode SACD in software, it was expected that the PS3 would be able to. SCE began the development in a relatively earlier stage. But even at the beginning of this year the SACD decoder was 6 times slower than realtime to convert surround DSD sound into PCM.
• The manager of the Software Platform division at SCE who were in charge of software codecs and players estimated it'd be impossible to finish if they kept that pace. A developer from the Sony HQ who developed softwares for VAIO PC came to SCE and they assigned the development of an SACD decoder codec to him.
• SACD is stored in the DST format (= compressed DSD). DST changes compression methods and parameters every 1/75 seconds, which eats huge processing load when decoding. In the first 2 months the developer optimized it into realtime processing. Then he threw away the old source code and wrote a faster new codec in 3 weeks with the knowledge he had gained. It uses 5 SPEs - 3 SPEs for DST decompression, and 2 SPEs for DSD to PCM conversion.
• After that, he debugged it while consulting the professional audio equipments division of Sony that
  developed the DSD format itself. It took 6 months.
• Then the audio tuning specialist at the audio division of Sony began to use a PS3 to check the sound of the then unreleased HD receiver TA-DA3200ES. He pointed out where to fix in the PS3's digital audio processing to SCE. It was in the early October, and the dynamic range at that time was 140dB which was the initial goal set by another Sony developer who developed DSD. The PS3 firmware version 1.10 is this version with a few updates. The decimation filter of the SACD decoder outputs at 24bit/88.2kHz.
• However, last Friday, Honda went to a place for the interview with Ken Kutaragi for some audio/videophile magazine. They brought there an even newer version with a decimation filter at 24bit/176.4kHz. Also, the 64-bit DP internal data of the decimation filter is rounded down to 30-29-bit instead of 24-bit for the output. The dynamic range is over 170dB and the theoretical number reaches 180dB in 30-bit. Honda says its sound was really good even when compared with the sound of the 1.1 version firmware. The Sony developer attributes the goodness to the fact that the software SACD codec of the PS3 processes all data in 64-bit double precision. This new firmware version will be available when the BD remote is released in December.
• As for improving CD sound, upsampling is apparently easy by writing a FIR filter. But it is not yet in the PS3 software player as it takes some time to choose an appropriate upsampling function and noise shaping algorithm.

The #2 is about the BD video player.
http://pc.watch.impress.co.jp/docs/2006/1130/mobile358.htm

• Since the standards for BD-ROM such as BDMV and BD-J were delayed, particular player functions were developed later while 2 years has already passed for the development of software decoding function for codecs such as H.264.
• H.264 decoding itself was not very difficult for Cell with moderate optimization and they could play a movie in realtime at the first try unlike very difficult SACD optimization. However, because they began the development without knowing the final Blu-ray standard, they set the goal very high for decoding 2 full HD H.264 streams at 40Mbps simultaneously. Besides the clockspeed of the devkit was lower than the final product which made the development difficult. The current decoder can decode full HD H.264 with 3 SPEs.
• The current BD/DVD player for the PS3 does internal pixel processing at 16-bit per RGB. (The output depends on the display color depth.) Though the 1.0 firmware was 8-bit per RGB, Kutaragi ordered the change of the design at the final product review and it was upgraded to 16-bit in the 1.1 firmware.
• It's still not enough for TV and theater projectors that can display the original YCrCb stored in BD and DVD. For example the current PS3 player lacks gradation in brighter and darker parts of pictures when compared to Panasonic DMP-BD10. The reason why the internal processing is done in RGB is because RSX can't have 2 color spaces at the same time. Honda suspects they used RGB for the player because in the prototype design they planned to overlay XMB in RGB onto the picture of BD/DVD. In the final design XMB is not overlayed onto the player.
• Actually Kutaragi also ordered the development of the version with YCrCb internal processing at the final review. In the firmware version released in December it becomes possible for a user to choose RGB or YCrCb.
• The current player converts interlace to progressive only for SD movies. Right now SCE developers are working to improve DVD picture quality after they implemented YCrCb. After that it's planned to do something for 1080i to 1080p conversion. Though the RAM size can be an obstacle for it, SCE developers say they can do it by splitting the load between Cell and RSX.
• Currently there are complaints from users about non-existent DVD upscaling in the PS3. As for the interlace-to-progressive conversion before upscaling, the current player has it already. There was a team at the division for broadcast equipments at Sony that does research for improving image quality by using the NVIDIA shader language. They ported it onto RSX. After Cell does noise reduction and other filters, RSX does interlace-to-progressive conversion. Though the current algorithm has bugs for some video sources, SCE says the conversion precision will be upgraded by future updates. Also the noise reduction filter is currently optimized for video sources with relatively many MPEG noises recorded with a video recorder. SCE knows lack of picture details because of it and will provide new default values for noise reduction by checking recording formats and media IDs for DVD discs. As for upscaling, they are doing the research to develop a high-quality multi-tap upscaling filter that balances the load between Cell and RSX. They also plan to use the non-original luminance information generated in upscaling for HDMI 1.3 deep color.
• Currently it's known that the audio quality of DTS is especially good compared to other audio codecs as heard in playing 480p DVD via HDMI with more bandwidth for the audio. SCE don't know the definitive reason. They just ported the reference source code provided by DTS with as high precision as possible.
• An SCE developer recommends trying 1.5x fast-forward playback in the PS3 BD player to see the power of Cell. When it's connected to a display via 1080/60p, it becomes very smooth as Cell has an enough margin for video decoding. In 1.5x fast-forward playback it decodes all frames then inserts them into 60fps with sped up audio.
• SCE declared that they'd support 1080/24p in the PS3.

 

[Carl B]

One, what can be said?

As always, you bring us the news we need and want.

Awesome news! All of my PS3-as-Blu-ray-player fantasies are coming true...

 

[Bad_Boy]

Sounds great one, thanks for the news.
I guess we can expect another small firmware update past 1.11 in early december then?

 

[inefficient]

I don't think there are any H.264 BR movies to test the 1.5x 60fps fast-forward playback mode with. I know it works fine with standard DVD and MPEG2 BR movies.

The plans for upscaling and better filtering for DVD sound very good though.

Also I want the PS3 remote control already!

 

[Carl B]

The 1080p/24 playback will be a big bonus to the videophile crowd as well, who already are very warmed up to the PS3 as a BD player considering it's not the typical offering.

 

[plat]

I don't think there are any H.264 BR movies to test the 1.5x 60fps fast-forward playback mode with. I know it works fine with standard DVD and MPEG2 BR movies.

The plans for upscaling and better filtering for DVD sound very good though.

Also I want the PS3 remote control already!

X3 from Fox is in AVC

 

[msia2k75]

There will be others mini-stories about the PS3 like this coming soon?

 

[Clockwork]

http://pc.watch.impress.co.jp/docs/2006/1130/mobile358.htm

Currently there are complaints from users about non-existent DVD upscaling in the PS3. As for the interlace-to-progressive before upscaling, the current player has it already. There was a team at the division for broadcast equipments at Sony that does research for improving image quality by using the NVIDIA shader language. They ported it onto RSX. After Cell does noise reduction and other filters, RSX does interlace-to-progressive conversion. Though the current algorithm has bugs for some video sources, SCE says the conversion precision will be upgraded by future updates. Also the noise reduction filter is currently optimized for video sources with relatively many MPEG noises recorded with a video recorder. SCE knows lack of picture details because of it and will provide new default values for noise reduction by checking recording formats and media IDs for DVD discs. As for upscaling, they are doing the research to develop a high-quality multi-tap upscaling filter that balances the load between Cell and RSX. They also plan to use the non-original luminance information generated in upscaling for HDMI 1.3 deep color.

I know that this info is suppose to be related to the Bluray playback capabilities, but I wonder if the underlined issue above is also the reason we are seeing IQ issues on PS2 games that don't support progressive scan (or use 512x512 buffer)??

Hmm....

 

[inefficient]

http://pc.watch.impress.co.jp/docs/2006/1130/mobile358.htm


I know that this info is suppose to be related to the Bluray playback capabilities, but I wonder if the underlined issue above is also the reason we are seeing IQ issues on PS2 games that don't support progressive scan (or use 512x512 buffer)??

Hmm....

They are talking about upscaling and filtering for DVDs not BR. And it is not even implemented in the current version of the playback software. So I don't see how it can be related.

The PS2 problem seems to be just a bug with the deinterlacing. And hopfully a firmware update will fix that. Sony has already explicitly said they will not implement upscaling or filtering for PS2 titles because they want the games to be seen the way the designers originally intended them to be seen.

 

[one]

Maybe I should have used the word "deinterlacing" instead of "interlace-to-progressive conversion" As the original text repeatedly uses the word "I/P conversion" I'd forgot there was a more natural word for it...

 

[Shifty Geezer]

The first in the series is about the SACD player.
http://pc.watch.impress.co.jp/docs/2006/1122/mobile357.htm

Sounds technically great, but I have to say, who the heck will benefit?! I guess it'll help to sell PS3's as low-cost, high quality AV equipment to audiophiles, but I'd rather have seen some better game and OS features, such as scaling! I think it's more important at this point to target the uses of the mainstream users, then the 'elite'. Accessing someone's iPod contents directly, with it's crappy low-bitrate compressed music, is far more beneficial then offering 32 bit, 260 KHz uncompressed 8.1 audio streams that two or three people in the world will notice!

 

[crazygambit]

Thanks for the translation one. Funny, it never occurred to me that SACDs were that hard on the processor. And it's a feature I'd completely forgot PS3 had. I wonder if it's worth the investment (a pretty capable engineer from the looks of it, for six months). Who listens to those? I'm quite happy with my 128kbs MP3s

Edit: Crap Shifty beat me to it.

 

[London Geezer]

Sounds technically great, but I have to say, who the heck will benefit?! I guess it'll help to sell PS3's as low-cost, high quality AV equipment to audiophiles, but I'd rather have seen some better game and OS features, such as scaling! I think it's more important at this point to target the uses of the mainstream users, then the 'elite'. Accessing someone's iPod contents directly, with it's crappy low-bitrate compressed music, is far more beneficial then offering 32 bit, 260 KHz uncompressed 8.1 audio streams that two or three people in the world will notice!

Shifty, not everyone is a laggard like you! Reports show that SACD sales have increased 300%!! 6 SACDs were sold last month!

 

[Clockwork]

They are talking about upscaling and filtering for DVDs not BR. And it is not even implemented in the current version of the playback software. So I don't see how it can be related.

The PS2 problem seems to be just a bug with the deinterlacing. And hopfully a firmware update will fix that. Sony has already explicitly said they will not implement upscaling or filtering for PS2 titles because they want the games to be seen the way the designers originally intended them to be seen.

Which I noted. I am aware the post was regarding Bluray playback, but this little tidbit:

RSX does interlace-to-progressive conversion. Though the current algorithm has bugs for some video sources, SCE says the conversion precision will be upgraded by future updates

had me wondering if these same bugs in the deinterlacing is affecting the image quality of PS2 games on PS3.

 

[Shifty Geezer]

Which I noted. I am aware the post was regarding Bluray playback, but this little tidbit:

had me wondering if these same bugs in the deinterlacing is affecting the image quality of PS2 games on PS3.

Sounds likely. Shame the deinterlacing didn't benefit from whatever this did!

Currently it's known that the audio quality of DTS is especially good compared to other audio codecs as heard in playing 480p DVD via HDMI with more bandwidth for the audio. SCE don't know the definitive reason. They just ported the reference source code provided by DTS with as high precision as possible.

That's just fantastic. 'It's good, but we've no idea why!' Perhaps it's the same factor that makes PS1 such a great audio player? And maybe PS3 gets even better if you don't switch it off?!

 

[London Geezer]

That's just fantastic. 'It's good, but we've no idea why!'

Of course we do. It's because it's better.

 

[wco81]

Don't see them supporting the iPod since they have ambitions with their MP3 players still.

AAC would be nice.

There are now NAS units with iTunes server for streaming over the network.

Would be nice if it can decode AAC and MP3 from such sources.

Remember when people were speculating before E3 2005 that Sony might collaborate with Apple to give some connectivity with iPod? Never happened.

 

[Shifty Geezer]

Don't see them supporting the iPod since they have ambitions with their MP3 players still.

All it needs is access to the iPod directory structure. The rest is already there AFAIK. The problem as I undertand it is that in accessing media on any attachable media store, PS3 assumes a directory structure rather then searching for suitable files automatically. I have read that you can browse a connected iPod to find and play the music. It needs to be more user friendly though, and that I think would be a lot more appreciated then being the world's best player of an obscure and irrelevant audio format. How many people can afford audio setups that make the benefits of SACD even audible?!

 

[London Geezer]

Don't see them supporting the iPod since they have ambitions with their MP3 players still.

AAC would be nice.

There are now NAS units with iTunes server for streaming over the network.

Would be nice if it can decode AAC and MP3 from such sources.

Remember when people were speculating before E3 2005 that Sony might collaborate with Apple to give some connectivity with iPod? Never happened.

PS3 does support AAC and in fact you can play your iPod music through it. It's a bit fiddly but it works.

 

[Bobbler]

# H.264 decoding itself was not very difficult for Cell with moderate optimization and they could play a movie in realtime at the first try unlike very difficult SACD optimization. However, because they began the development without knowing the final Blu-ray standard, they set the goal very high for decoding 2 full HD H.264 streams at 40Mbps simultaneously. Besides the clockspeed of the devkit was lower than the final product which made the development difficult. The current decoder can decode full HD H.264 with 3 SPEs.

I found this part kind of funny, because it reminded me of the FUD Amir was spreading trying to get people to doubt PS3's ability to deal with high bitrate BR movies (MS apparently had so much trouble getting HD-DVD decoding working, because it stresses their CPU so much, iirc -- he was trying to say that Cell would have possibly even worse issues because it only had 1 PPE). It seems to me it handles it pretty easily... the system noise/lack of fan running full speed seems to confirm that too.

Definitely shows one of Cell's strengths over X360's CPU. MS has been saying HD-DVD playback stresses the system more than anything (besides Gears, apparently) and Amir confirmed it was tough for them to fit it all on the CPU... meanwhile everything we've seen from SCE/PS3 seem to indicate it decodes even ridiculous bitrate streams with rather ease. Now if only it was that easy to get the performance out in games.

# An SCE developer recommends trying 1.5x fast-forward playback in the PS3 BD player to see the power of Cell. When it's connected to a display via 1080/60p, it becomes very smooth as Cell has an enough margin for video decoding. In 1.5x fast-forward playback it decodes all frames then inserts them into 60fps with sped up audio.

The X-men 3 movie is a pretty nice example of this... there are scenes in that movie that hit high 30 mbps in AVC (I saw some 37+, which actually kind of surprised me) which don't seem to skip frames at all when viewed in 1.5x (sound also plays too, which is kind of funny to hear at times).


Overall, this is pretty exciting news. Most of that stuff was expected (as far as updates go), but very nice to see it confirmed. Seems most of it should be in a December update (1.2?).

I'm kind of confused though, are they saying there will be a fix for the below dark and over bright clamping? (using YCrBr instead of RGB? or will there be a fix for RGB too?) That seems to be a concern some currently have with PS3 as a BR player. 1080p24 was also a concern, but that's definitely being added.