[FFmpeg-user] how to "play" uncompressed video across an network?

Thomas Worth dev at rarevision.com
Tue Feb 21 19:20:14 CET 2012


On Tue, Feb 21, 2012 at 10:13 AM, Donald McLachlan
<Donald.McLachlan at crc.ca> wrote:
>
>
> On 21/02/2012 12:28 PM, Thomas Worth wrote:
>>>
>>> Worry first about your network infrastructure. Back of the envelope
>>> calculation: assuming you're talking about a 4096-wide 16:9 image,
>>> that'll
>>> be 1940 pixels high, and even at 8-bit, each frame will weigh in at the
>>> best
>>> part of 23MB, without any sort of format overhead or audio taken into
>>> account. That's nearly 600MB a second, which is about half the
>>> theoretical
>>> total bandwidth of your 10 gig network. Certainly you won't be doing more
>>> than one stream at once.
>>>
>>> Within that you can use anything that will allow you to remote access the
>>> file - although I'd be interested to see if most samba implementations
>>> could
>>> keep up!
>
> Hi Thomas,
>
>> I believe this is usually done with a SAN via iSCSI, in the case of
>> Ethernet. You'd basically be accessing the host as a block device
>> rather than through an NFS or Samba server. Streaming 4K uncompressed
>> video over a Samba network sounds like massive amounts of pain waiting
>> to happen.
>>
>> Also, I wouldn't be playing the video in MPlayer. I'd be sending raw
>> RGB to a SDI output device so I could watch the result on a proper
>> calibrated display / projector. That's typically how it'd be done in a
>> proper post facility.
>
> We'd love a 4k or 8k display (or even projector), but for now what we have
> is a SAGE wall.

Yeah, I saw where you mentioned that in the previous email. You also
mentioned trying to decode JPEG 2000, which is impossible at those
resolutions without some type of hardware assistance. There are some
CUDA implementations that will run on Nvidia cards, but I doubt this
is anywhere near being implemented in avcodec.

You might try HuffYUV as a codec. It is supposedly a very fast and can
also run in subsampled mode, which will help cut down on bandwidth
even more. Also, have you tried Motion JPEG (not JPEG 2000)? You
should be able to compress the image, it's just JPEG 2000 is a bad
choice because it takes so much power to run in realtime.


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