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FS#8598 - FM Recording disk thrashing

Attached to Project: Rockbox
Opened by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 03:23 GMT+2
Task Type Bugs
Category Recording
Status Unconfirmed
Assigned To No-one
Player type Sansa e200
Severity Low
Priority Normal
Reported Version current build
Due in Version Undecided
Due Date Undecided
Percent Complete 0%
Private No

Details

When recording, as file size reaches 25.2MB and again at 52.4MB respectively, disk thrashing noise drowns out the recording for about 2 minutes.
This occurs at about 27.5 minutes if recording as mp3.
And about 5.25 minutes if recording as wav.


I am assuming that Rockbox is filling a cache and then dumping the file to disk all at once.

I would expect it to write quietly. Even if it where to write on the fly, the noise would be reduced to short bursts. 2 minutes of interruption is just not acceptable. I missed out on important information during those 2 minute periods.

How can we eliminate write noise altogether? Or at least in the recording itself.


Select 'FM Radio' Choose your station.
Then from the menu select 'Recording'
Press 'play' or 'Rec' to begin recording.
Wait for file size to reach about 28MB. Then stop.

I can also provide recordings if necessary.

*note: I also had the USB cord attached to give better FM reception.
tested on e260 & e280
Rockbox Version: r15988-080102

Thanks
This task depends upon

Comment by Paul Louden (Llorean) - Tuesday, 12 February 2008, 04:49 GMT+2
There's no reason the disk spinning should create noise in an FM recording. The mic is not used. Did you have a headphone cable attached to improve reception?
Comment by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 05:09 GMT+2
True the Sansa does not have a spinning disk. The mic was not being used. I did have the headphones attached. That's how I first noticed the noise. It was so loud I had to pull the earbuds out of my ears. I could not hear what the speaker was saying for 2 minutes. I believe it is accessing the flash as I noticed the disk access icon at top of the screen.
Comment by Paul Louden (Llorean) - Tuesday, 12 February 2008, 05:20 GMT+2
Was the noise actually present in the recording itself, or just audible when it was recording: Did you listen to the file on your computer (not your Sansa)?
Comment by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 05:32 GMT+2
The noise was audible in both the recording (file playback) and through the headphones while recording. Would you like me to upload a sample? I'll have to crop the file to fit the 2MB upload limit.
Comment by Paul Louden (Llorean) - Tuesday, 12 February 2008, 05:35 GMT+2
Did you play your file on your PC, or on your Sansa? I asked that question very clearly, and you didn't state yes or no.
Comment by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 05:40 GMT+2
I played the file on my PC. I also played the original on the Sansa. Same results. Attached is a sample...
   R_FM_080210-093831.mp3 (378.8 KiB)
Comment by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 05:42 GMT+2
Lets try a zip of that file...
   R_FM_080210-093831.mp3.zip (348.4 KiB)
Comment by Garry Nichols (nulesus) - Tuesday, 12 February 2008, 06:27 GMT+2
I've been trying to reproduce this here at home and I am having mixed results. I appears that the noise is more audible at or around 104.10mhz
However, When I tested this yesterday on-site (Where I began to experience this problem) with the original firmware. I did not have any noticeable problems. Here at home I do NOT have a station near 104.10mhz
Comment by Michael Sevakis (MikeS) - Tuesday, 12 February 2008, 13:52 GMT+2
I have only gotten interference if reception was dodgey and never anything that sounds like that. That you say it's taking two minutes to write is also rather strange though I agree that a flash storage device could flush almost constantly or at least very often so that the duration of each is greatly reduced. The recording code was geared towards HD based players.

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