ecorder that runs on
mains. So when
Getty Images
2
expressed a preference for
4:2:2 and the new SRW-1 became available - Mamma Mia! A
smaller, lighter, less power hungry, higher quality alternative to
HDCAM.dont we love Moores law!
The HDCAM deck would remain a back-up as ballast in the
boot of the production van rather than sacrificing its weight for
fuel in the helicopter.
Switch on
The SR field recorder is comprised of two parts. The SRW-I
recorder and the SPC processor. The combo is being called the
SRW-1 field recorder by most.
We can assume that the SRW does most of the work; it
contains the tape drive and is considerably heavier and more
power hungry than the SPC processor.
The form factor is novel and bizarre, in looks at least. The SRW
clamps onto the top of the SPC. However despite looking like a
double storey ghetto blaster its functionality reverts to the
familiar Sony field recorders of a top tape loading slot with inputs
and outputs down one side and a big handle across the top.
However there is one difference in previous field recorders
which is the lack of in-built controls, other
than eject, on the unit. A cool looking remote
control is provided which can be extended
from the recorder by cable. It displays
timecode, audio levels for 12 channels,
warnings, channel condition time frame rate,
conventional VTR buttons a mini- jog push
button and curious large wheel which didnt
seem to do much on the pre-production
model we were using.
The remote can be secured to the top of
the SRW-1 with a hot shoe. Id prefer a set of
emergency use buttons somewhere as the
remote control or its cable could be damaged
in the field. Without the remote its the end of
the shoot!
If the first impression is the bizarre looks the
second impression is its sound. The cooling
fans were on continuously and made
considerable noise. Interior sound recording
within a distance of six feet of the unit would
be troublesome. For dramas I imagine well
ventilated soundproof box may be needed or
a longer extension cable for the remote so the
unit can be operated off set but monitored on
the remote on set.
However as the unit itself did not get too
warm there may be room for reducing the
airflow. The power management is often
handled in software so I would hope that the
fans would become a little quieter in
production models.
Part of the reason for the noise is that the
combined power drain is 95 watts so there is a
lot of heat to dissipate by fans, The SRW-1
draws 60 watts and the processor 35 watts.
Sony SRW-1
1
Field Recorder
MIKE BRENNAN discovers that Sonys new SR field recorder has hidden depths
review
SRW-1
40
october | november 2004
high definition
W
The SRW-1 combo pre-flight
1
www.cinealta.com
2
www.search.gettyimages.com Careful attention must be made that the power supply and
cable is capable of providing at least eight amps.
The most recently built field equipment is designed for 50 to
70 watt maximum and so will be struggling with 95 watts. A
trusty old AC500 can cope with 120 watts as can some
selected new power supplies.
Frame rate change
I also enlisted the help of the Black Box Video battery box,
The Big One, capable of running the recorder for almost two
hours if we blew a fuse in the aircraft and useful for checking
back recordings on the ground without derigging the aircraft.
About the only trap I found, and was warned about in
advance, occurs when changing frame rates, as one must
adopt the f500 routine of ejecting the tape and rebooting.
In fact the tape must be ejected before the new frame rate is
selected in the menu, otherwise even if you reboot the frame
rate will not change.
12 channels of audio are available in the SR format, however
the SRW has only four Canon 3-pin inputs. There is AES/EBU
digital input and output to access the other channels.
Video inputs are split into A and B channels. When
recording 4:4:4 two channels of video are required from the
camera (dual stream). When recording 4:2:2 the A channel is
the default input.
Monitoring outputs are clean HD-SDI for A and B
channels and a second monitoring HD-SDI output with
switchable character generator overlay. When inputting
4:4:4 the HD-SDI output provides a useful means of
monitoring as the processor converts RGB to Y PB PR.
A SDI output is available and can be configured for squeeze,
crop or letterbox. The SDI output cannot be switched to
composite. It creates 2:3 pull down when shooting at 23.98p
Timecode in and out are positioned on the SRW-1. HD
reference is on the SPC. There is one power switch for each
SRW-1
review
high definition
october | november 2004
41
The SRW-1 does have sound issues
from the cooling fans
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iQ is DI Star Wars image courtesy of Lucas Digital The other issue is susceptibility of the recorder itself to RF
radiation from aircraft systems. Flying fashionably low near
transmitter masts we had a twenty second RF hit on tape. This
kind of RF interference close to powerful sources is not
unusual. The effect was quite obvious on the monitor and on
replay the interference on tape occurred at the same time and
for the same duration as it presented itself on the monitor at
the time. This experience suggests that the recorder itself is
well shielded and the RF was being picked up from the camera
head or the two lengths of six foot cable between gimbal and
recorder.
What one fears most with a new recorder is exterior RF
interference that goes to tape that is not evident whilst
shooting on a monitor.
The unit can also record two separate HD-SDI 4:2:2 streams
from two sources. Rumoured to be prompted by a request by
James Cameron who wants to shoot more 3D using HD, this
feature will be available to all.
So a two camera drama couldnt be easier to synch up.
However the SRW must be used to digitise the rushes as the
SR5000 studio deck does not support the dual picture mode.
Compression ratios
The most versatile feature of the SRW1 is its ability to switch
compression ratios.
In 4:2:2 mode it compresses 2.7/1 for a data rate of
440Mbs.
In 4:4:4 SQ mode it compresses 4.2/1 for a data rate of
440Mbs.
In 4:4:4 HQ mode it compresses 2/1 for a data rate of
880Mbs.
In stereo 4:2:2 mode two separate 4:2:2 pictures are
recorded at a rate of 880Mbs
It achieves the 880Mbs rate by running the tape at double
speed, thus halving the maximum recording time to
25minutes. A future upgrade will also enable the SRW to
record 720 60p.
Not only does it switch tape speed it also switches
compression schemes. The SR format uses intra-frame
compression for progressive and intra-field compression for
interlace recording.
As usual with new HD kit there is a need to create your own
terminology, we need a description of stereo recording in
compressed 4:2:2 that is not confused with dual stream 4:4:4.
How about stereo 4:2:2?
It may be that 4:2:2 recording will be superior for some
projects due to the higher compression in 4:4:4. The double
speed 4:4:4 recording will be the choice for bluescreen, normal
speed 4:4:4 with 4.2/1 compression will need to prove itself.
It is useful to have a choice!
Daisy chaining
Up to three SRW-1s can be daisy-chained together so
duplicate recording or continuous recording without stopping
is possible from the one SPC.
We chose 4:2:2 due to the increased recording time in
review
SRW-1
unit, with the SPC having the master power switch.
The new menu isnt too bad, but allow 30 minutes for
familiarisation to reduce the likelihood of panic attacks.
Selecting format and frame rates is straightforward and both
options are on the same page in the menu. There is a line of
buttons on the remote that jump the menu to time code,
video, audio, system and home. This is very helpful but time
code is adjusted by jog wheel and is some what buried in the
menu and with Italian flight time costing 26 a minute the
wasted seconds add up.
Recording is within
1/2
second from pause mode. Colour
bars and black can be generated, a very useful feature, a wider
choice of colour bars would be welcome.
Media
The machine accepts small
cassettes only. A 40 minute will run
48 minutes at 25p; 50 minutes at
24p when recording 4:2:2. When
recording 4:4:4 or stereo recording
times are reduced.
Sony say that they have
improved tape technology this is
borne out by the tape length being
longer, however as the tape travels
faster there is no significant
change in running time over
HDCAM tapes.
The cassette shell is a beige
white reminiscent of the colour of
the first floppy disks and has
improved finger grips to help open
the case.
Genesis SRW
A modified SRW sits a top the
Genesis
1
camera. The question
is whether the Genesis has an internal MPEG processor or if all
the signal processing is housed in the SRW. The likelihood is
that most of the processing takes place in the SRW-1. You may
question then the size of the SPC.
There is a future upgrade that will install a fibre optic
connector on the unit so the form factor is about right for
remote recording of a location drama and any studio
programmes. A camera remote control can be connected to
the unit and presumably this signal will be carried over the