High bit-rates on BD crashes players? Any truth?

[Lyris]

A friend of mine who's authoring BDs was told by a post house that they tend to aim for a max bit rate of 35mbps and never allow their AVC encoder to reach the full 40mbps. The reason: for "older/cheaper players".

To me, that sounds like leftover superstition from the DVD days (which I believe was limited to playing from bad DVD-Rs rather than pressed discs).

Has anyone heard of cheap BD players choking with 40mbps video or can we safely ignore this?

Keep in mind I'm talking about BD, not "BDMV on DVD".

[mp3dom]

Honestly I don't know. I've seen a lot of BDs with max bitrate set to 38 Mbps even for those discs with only a simple stereo PCM audio (so they limit it intentionally). You can do the same, considering that the 2 Mbps difference at that high bitrate is probably unnoticeable at all (also, with VBV you can have spikes above 40 Mbps for a short period if you need to cover very complex scenes)

[Stacey Spears]

I have used 40 Mbps on my two Blu-ray discs. I am not aware of any problems, one has been on the market for over two years. In addition to the 40 Mbps video, they both include lossless audio. I also re-encode to try and use up the full VBV, so I have seen peaks on the PS3 video bitrate meter > 60 Mbps. I do this as a stress for a player, since it is a test dsic.

The DoStudio encoder limits the peak bitrate to 38 Mbps using the excuse that some players can't handle for 40 Mbps.

Many of the cheap players are using the UniPhier chip from Panasonic, which is not a low quality decoder.

[unix_sansei]

I've found that the cheap low-end players crap out on high bitrate blu-ray. I encoded my film at video 45MBs++ with 6 channel wav @96kHz and tried it out at best buy on their consumer players, they have definite video artifacts and blocking with the 'el cheapos'. I've seen it as did the people who gathered at best buy to watch it.

I tell everyone if the video looks crappy, it's because their player is cheap.

[nixo]

I've found that the cheap low-end players crap out on high bitrate blu-ray. I encoded my film at video 45MBs++ with 6 channel wav @96kHz and tried it out at best buy on their consumer players, they have definite video artifacts and blocking with the 'el cheapos'. I've seen it as did the people who gathered at best buy to watch it.

I tell everyone if the video looks crappy, it's because their player is cheap.

Well, that's hardly surprising. Your disc is way out of blu-ray spec.

--
Nikolaj

[unix_sansei]

Well, that's hardly surprising. Your disc is way out of blu-ray spec.

--
Nikolaj

do you have a clue of what you're talking about?

RTFM or the spec like I did.

or least wikipedia if you're too lazy.

"BD Video movies have a maximum data transfer rate of 54 Mbit/s, a maximum AV bitrate of 48 Mbit/s (for both audio and video data), and a maximum video bit rate of 40 Mbit/s." any engineer will tell you, just like I will, that there is always padding in the specifications for a peak or burst in the data stream. I took 40Mb to be a sustained transfer rate and that is baseline. So for you to say my encoding is "way" out of spec to me is ludicrous and/or ignorant.

[mp3dom]

Maxrate for video is 40 Mbps (excluding DPB/VBV which surely allows spikes above 40 Mbps for a (very)short period of time). The remaining 8 Mbps are for audio. If you use more than 8 Mbps for audio you need to lower the video maxrate. Basically you can go up to 40 Mbps for maxrate unless your audio use more than 8 Mbps. What program did you use to compile your BD? A maxrate of 45 Mbps (for video, excluding DPB/VBV) is out of specs.

[kieranrk]

I took 40Mb to be a sustained transfer rate and that is baseline. So for you to say my encoding is "way" out of spec to me is ludicrous and/or ignorant.

It is ludicrous for you to take what is clearly defined as a maximum value in the spec and use it as a baseline.

[Stacey Spears]

I encoded my film at video 45MBs++ with 6 channel wav @96kHz

As it has been stated, maximum video bitrate is 40 Mbps. If you are using 6-channels of 24-bit / 96 kHz audio, that will consume 13.82 Mbps of the allowed 48 Mbps. This means the peak video bitrate will need to be less than 35 Mbps. Even when using lossless compression, like TrueHD or DTS-HD MA, you will need to be down around 35 Mbps for video if you want to pass mux and verification.