Not emptying the time shift buffer unnecessarily

[reason]

Sometimes when viewing from the time shift buffer and a channel change happens accidentally or because of a recording event, the whole buffer is emptied unnecessarily and previous channel data is lost. So, I'd like to suggest continuing filling the buffer normally overwriting the oldest data only if the buffer becomes full, but with storing pointers to every channel's sections in the buffer. A certain channel's data in the buffer would be only available if the user is tuned to this channel. For example, if there is 1 minute of channel A in the buffer and the user switches to channel B and watches 2 minutes and switches back to channel A, its 1 minute becomes available again in DD interface. If the user switches again to channel B, its previous 2 minutes becomes available to the user, and so on. DD can also have the ability to jump to and display the unviewed parts of the channel in the seeking interface. It would be a nice feature…
Thanks.