#181 wget'ing something makes audio chirp on host

v0.7.x (release)


I would like to report a strange thing that I found using colinux 0.7.9-RC4.
When I use an ArchLinux guest and wget something (preferably something large like an iso) my foobar player on the host (Windows XP 32bit) plays chirps through my music (MP3 files). When wget finishes or is killed, it keeps chirping until the buffer is refreshed (typically 0.5 buffer length).
So it seems the audio buffer gets corrupted while it is filled.

But it gets stranger:
- Media Player Classic with ffdshow seems to chirp only when I play an audio or a video file which has AAC or AC3 audio.
- MP3 in MPC is not affected when decoded with the libmad decoder, but does chirp when decoded with libavcodec.
- Rarely I see artifacts in the video while wget'ing.

- When I lower the buffer length in foobar (to 50ms) and start wget, the chirping is instant.
- When I increase the buffer in foobar (to 16s) and start wget, the chirping takes a long while to kick in, but keeps on going while wget is finished or killed.
- Using different output precisions in foobar gave me these results:
-- 8bit + non-dithered: chirpes
-- 8bit + dithered: doesn't chirp
-- 16bit + non-dithered: doesn't chirp
-- 16bit + dithered: doesn't chirp
-- 24bit: chirpes (dithering unavailable)
-- 32bit: not supported by soundcard, sounds awful.
- BTW: My soundcard is a Soundblaster Audigy SE 24bit.

- Firefox on the host seems to crash a lot more when wget'ing in a guest and a flash movie is playing on the host (youtube).
- Rarely I see artifacts in youtube video's while wget'ing.

So I tried isolating the problem:
- dd'ing 200megs from /dev/full to a file. No chirping.
- wget using an external server (linux iso fetching). Chirpes.
- wget using an internal server (binary blob fetching). Chirpes.
- Running netio, client on guest, server on host (tcp using default port and port 80). No chirping.
- Running netio, server on guest, client on host (tcp using default port and port 80). No chirping.
- Using pcap-bridge instead of ndis-bridge. Both chirp.
- Using Debian Lenny guest, I recently upgraded the Archlinux guest and it uses quite cuting-edge packages, Debian should be more old fashioned. Still chirpes.
- Written a little program to do a lot of floating point operations. Doesn't chirp.
- Written a little program to do a lot of memory allocation operations. Doesn't chirp.
- wget using the guest as server (binary blob fetching), no real network involved. Chirpes.
- Download the binary blob from the guest to the host (reverse http transfer). Doesn't chirp.

Seems only wget causes the problem to surface. And it seems to me like a memory corruption somewhere.

Hopefully this rings a bell with someone and can be fixed easily. Keep up the good work.



  • Keith

    Keith - 2011-02-22

    I tested a few versions of colinux, and it seems like a long lived problem:

    v0.7.9-20110216 (RC4) chirpes
    v0.7.9-20110205 chirpes
    v0.7.9-20110204 chirpes
    v0.7.9-20110125 chirpes
    v0.7.9-20101122 chirpes
    v0.7.9-20101114 chirpes
    v0.7.9-20101113 untestable, no reiserfs
    v0.7.9-20101109 untestable, no reiserfs
    v0.7.8-20100727 untestable, no reiserfs
    v0.7.7.1 (20100702) doesn't chirp

    The versions without reiserfs baked-in should be tested by someone else. All my virtual machines need reiserfs to boot, sry.

  • Keith

    Keith - 2011-02-27

    Okay, today I tried testing the snapshots listed above which I haven't tested before.

    The results are:
    v0.7.9-20101113 chirpes
    v0.7.9-20101109 chirpes
    v0.7.8-20100727 chirpes

    In short, it seems this problem was introduced in July last year.

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