[ros-users] working with compressed bag files?

[Jack O'Quin]

On Sat, Apr 10, 2010 at 8:46 PM, Tim Field <tfield at willowgarage.com> wrote:
> The problem with gzipping an entire bag file is you lose the ability to do
> random access.  We're working on a new bag format for rosbag which
> internally uses compression and permits random access.  This is slated for
> ROS 1.1.3.
>
> For images, one option to consider is storing CompressedImage messages in
> your bag files (see compressed_image_transport).  A domain specific
> compression algorithm is always going to beat a generic one such as gzip.
>
> Tim
>
> On Sat, Apr 10, 2010 at 5:22 PM, Jack O'Quin <jack.oquin at gmail.com> wrote:
>>
>> Is there a rosbag option to read and write gzipped bag files?
>>
>> That would be useful. With images and point clouds bags can get really
>> large, and gzip can compress them quite a lot.

True, but I've been gzipping random bag files and getting files 6 or 8
times smaller. There's a lot of repeated data in them.
-- 
 joq