60D Max Bitrate?

[Dave]

Hi all,

I recently picked up a SanDisk Extreme Pro SDHC card (45MB/s) and
tried bumping up the bitrate on my 60D - but I was only able to get
CBR up to 1.4x or Qscale up to -8 without choking out the buffer. Even
at those settings, the buffer indicator is showing almost all the time
(at one block filled). Clearly the memory card is not the bottleneck
here - could this be the limit of the camera's speed itself? Has
anyone achieved higher bitrates on a 60D? Actual final bitrate max
appears to be around 65mbps.

[Alex]

Hi Dave,

According to our earlier card benchmarks (
http://groups.google.com/group/ml-devel/browse_thread/thread/77fc7e58dd86a7ed
), it seems the maximum write speed is limited due to a small buffer
used during recording. Probably there's a way to get around this if we
understand where the buffer is allocated and how to change its size.

I've added a section at the Bit Rate page, with maximum bitrate which
can be achieved, according to user reports. Please feel free to
improve it, or if you don't like to edit a wiki table, add your
suggestions here or on the talk page.

http://magiclantern.wikia.com/wiki/Bit_rate#Cards

I use Transcend Class 10 and bitrate can go up to CBR 1.3x. With my
class 2 (Kingston) card which I use for tests, I can record with CBR
0.9.

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[Dave]

Exactly what I was looking for. Thanks Alex.

On Aug 1, 5:05 am, Alex <broscutama...@gmail.com> wrote:
> Hi Dave,
>

> According to our earlier card benchmarks (http://groups.google.com/group/ml-devel/browse_thread/thread/77fc7e58...

[trip3980]

yeah its not going to budge past 1.4 and 1.4 is really pushing it. I
keep mine at a steady 1.3 CBR.

On Aug 1, 5:05 am, Alex <broscutama...@gmail.com> wrote:

> Hi Dave,
>
> According to our earlier card benchmarks (http://groups.google.com/group/ml-devel/browse_thread/thread/77fc7e58...

> ), it seems the maximum write speed is limited due to a small buffer
> used during recording. Probably there's a way to get around this if we
> understand where the buffer is allocated and how to change its size.
>
> I've added a section at the Bit Rate page, with maximum bitrate which
> can be achieved, according to user reports. Please feel free to
> improve it, or if you don't like to edit a wiki table, add your
> suggestions here or on the talk page.
>
> http://magiclantern.wikia.com/wiki/Bit_rate#Cards
>
> I use Transcend Class 10 and bitrate can go up to CBR 1.3x. With my
> class 2 (Kingston) card which I use for tests, I can record with CBR