From timur at freescale.com  Fri May  9 22:20:35 2008
From: timur at freescale.com (Timur Tabi)
Date: Fri, 09 May 2008 16:20:35 -0500
Subject: [Alsaplayer-devel] Is alsaplayer endian-safe?
Message-ID: <4824C023.2010207@freescale.com>

I don't think it is, at least not for WAV files.

When I try to play a WAV file on a PowerPC (big-endian) system, I get this:

alsaplayer -o alsa /usr/share/apps/korganizer/sounds/lightmag.wav
APLAY: Cannot identify WAV
APLAY: main_chunk = 52494646 -> 46464952
APLAY: chunk_type = 57415645 -> 45564157
APLAY: sub_chunk = 666d7420 -> 20746d66
APLAY: data_chunk = 64617461 -> 61746164
APLAY: Cannot identify WAV
APLAY: main_chunk = 52494646 -> 46464952
APLAY: chunk_type = 57415645 -> 45564157
APLAY: sub_chunk = 666d7420 -> 20746d66
APLAY: data_chunk = 64617461 -> 61746164

If you look at the chunk bytes, they're all reversed.

This is because of this code:

        if (wp->main_chunk == WAV_RIFF && wp->chunk_type == WAV_WAVE &&
            wp->sub_chunk == WAV_FMT &&

the 'chunk' fields are defined like this:

typedef struct wav_header {
        u_int main_chunk;       /* 'RIFF' */
        u_int length;           /* filelen */
        u_int chunk_type;       /* 'WAVE' */

        u_int sub_chunk;        /* 'fmt ' */
        u_int sc_len;           /* length of sub_chunk, =16 */

(let's ignore the fact that this code assumes that an integer is 4 bytes)

So when it tries to read wp->main_chunk from memory, it will treat the 4 bytes
as a big-endian integer, and WAV_RIFF is coded for little-endian only.

-- 
Timur Tabi
Linux kernel developer at Freescale


From andy at carapace-systems.com  Fri May 16 10:52:45 2008
From: andy at carapace-systems.com (Andy Hughes)
Date: Fri, 16 May 2008 10:52:45 +0100
Subject: [Alsaplayer-devel] mp3 volume
Message-ID: <482D596D.5040401@carapace-systems.com>

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From lemenkov at gmail.com  Fri May 16 14:12:48 2008
From: lemenkov at gmail.com (Peter Lemenkov)
Date: Fri, 16 May 2008 17:12:48 +0400
Subject: [Alsaplayer-devel] mp3 volume
In-Reply-To: <482D596D.5040401@carapace-systems.com>
References: <482D596D.5040401@carapace-systems.com>
Message-ID: <adf480660805160612h5cb93579xb24dd464f0ce1515@mail.gmail.com>

Hello All!

2008/5/16 Andy Hughes <andy at carapace-systems.com>:

> Does alsaplayer recognise and use the volume id3 tag on mp3s?

No.

-- 
With best regards!