Opened 20 years ago

Closed 20 years ago

#2115 closed patch (fixed)

MP3 encoding of captured audio produces static on PowerPC linux machines.

Reported by: zdevito@… Owned by: danielk
Priority: minor Milestone: 0.20
Component: mythtv Version: head
Severity: medium Keywords: mp3 ppc endian
Cc: Ticket locked: no

Description

I have the mythbackend running on a linux ppc machine--a powermac g4 (digit audio revision) running Ubuntu dapper. Using a Plextor PX-TV402U-NA I am able to record TV with uncompressed audio fine but using mp3 encoding produces static. I have tracked the problem to an endian issue in NuppelVideoRecorder. It looks like the audio is read from the sound card as 16-bit little endian data; this raw audio data is sent directly to lame library for encoding, but the lame library expects data in system byte-order. Swapping the bytes in the audio before sending the audio to lame fixes the problem. I have attached a patch that fixes the issue for big endian machines.

Attachments (2)

fixmp3encoding.diff​ (796 bytes ) - added by zdevito@… 20 years ago.
a patch that fixes the mp3 encoding endian issue
2115.patch​ (2.3 KB ) - added by danielk 20 years ago.
Updated patch

Download all attachments as: .zip

Change History (6)

by zdevito@…, 20 years ago

Attachment: fixmp3encoding.diff​ added

a patch that fixes the mp3 encoding endian issue

comment:1 by danielk, 20 years ago

Milestone: → 0.20
Owner: changed from Isaac Richards to danielk
Version: 0.19 → head

by danielk, 20 years ago

Attachment: 2115.patch​ added

Updated patch

comment:2 by danielk, 20 years ago

Type: defect → patch

zdevito, can you verify that the attached 2115.patch works for you?

comment:3 by zdevito@…, 20 years ago

Yeah, 2115.patch works for me. -- Zach

comment:4 by danielk, 20 years ago

Resolution: → fixed
Status: new → closed

(In [10724]) Fixes #2115. Bigendian fix for NVR. Allows MP3 encoding to work with PowerPC Linux.

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