From owner-freebsd-multimedia@FreeBSD.ORG Sun Dec 6 20:38:38 2009 Return-Path: Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 93F48106566C for ; Sun, 6 Dec 2009 20:38:38 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-bw0-f213.google.com (mail-bw0-f213.google.com [209.85.218.213]) by mx1.freebsd.org (Postfix) with ESMTP id 1E6CB8FC0C for ; Sun, 6 Dec 2009 20:38:37 +0000 (UTC) Received: by bwz5 with SMTP id 5so3047908bwz.3 for ; Sun, 06 Dec 2009 12:38:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; bh=6z3pHOJqsRm9dX1z9IwJXf06a1FSsE9f63+qWLdEd4s=; b=nh9XGuAoHTh7eM5aYLSC+ttjiPTqxCU3LgPZPXgPCD213jPMqb/lOXB2L+h3Z4rv2O HZ0kT9tUfb0ion5vYgbIpJFU275ssA59XmUL9qF94M7+j/OpEMv2RDhbLeKvtWni84zC 6tYCJBNDvaDFv+UCQ/FixDnD2N7LmkoOlG9iA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=jD0Id1lHufPnYfdf4ji9miJVmENeEreLSmuJ2VpcH1E0R0ga5MgfL52QieMIg2nvSH GHvlq4Jq0KXRw3NyLgox3j4eMUsZ1OK2lvRW2RLbeLjoh5NOjAY74tPicoF4g/52bjEJ RQtEdnjAFS63CundnKsJ7zsz0iX1pmHVLAsaU= Received: by 10.204.11.6 with SMTP id r6mr6073943bkr.29.1260131916926; Sun, 06 Dec 2009 12:38:36 -0800 (PST) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id 15sm1737827fxm.14.2009.12.06.12.38.35 (version=SSLv3 cipher=RC4-MD5); Sun, 06 Dec 2009 12:38:36 -0800 (PST) Sender: Alexander Motin Message-ID: <4B1C1649.30509@FreeBSD.org> Date: Sun, 06 Dec 2009 22:38:33 +0200 From: Alexander Motin User-Agent: Thunderbird 2.0.0.23 (X11/20090901) MIME-Version: 1.0 To: Christian Weisgerber References: <1260127380.00191226.1260114002@10.7.7.3> In-Reply-To: <1260127380.00191226.1260114002@10.7.7.3> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Cc: freebsd-multimedia@freebsd.org Subject: Re: DTS audio pass-through doesn't work X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Dec 2009 20:38:38 -0000 Christian Weisgerber wrote: > Configuration: > FreeBSD 7.2-STABLE amd64 > snd_hda, S/PDIF, AC3 and DTS-capable amplifier > dev.pcm.2.play.vchans=0, mixer vol 100 pcm 100 > > What works: > mplayer AC3 and DTS pass-through (-ac hwac3,hwdts) for DVDs etc > works fine. > > What doesn't: > Playing DTS audio that masquerades as 44.1kHz PCM data fails, e.g. > DTS audio CDs or corresponding WAV files. XMMS and mplayer should > just output this unchanged over S/PDIF and the amplifier should > recognize it as DTS and decode it. Except it doesn't. It reports > PCM 44.1 and plays noise. > > When I play the same audio data on OpenBSD, the amplifier recognizes > it as DTS-encoded and everything works fine. > > There must be an element in the FreeBSD audio systems that performs > some kind of transform on the audio data, killing the DTS signature. > Any ideas? Actually codec need to know what it plays now: PCM data or compressed stream. Some codecs able to control volume on digital outputs, using math, and they are able to bypass data untouched when they were told that it is a compressed stream. Setting volumes to 100% may not be enough in such case, as that 100% may mean anything, depending on codec. If you disabled vchans for that output, then sound(4) should not transform sound in any way. snd_hda(4) also doesn't do it. Codec digital output node can receive some options, controlling resulting stream, which I never tried to tune. May be there is some difference with OpenBSD, I don't know. -- Alexander Motin