In an exchange with Takashi regarding my proposal for changing some mixer control names, he recommended that I start a thread in attempt to reach consensus regarding a convention/standard for mixer control names in ALSA. My name-changing effort was complicated by the fact that, as Takashi put it: "Many apps assume either 'Master' or 'PCM' mixer exists." (Background: The only multichannel audio adapter to which I have access for testing is an Analog Devices AD1986A CODEC attached to an AC '97 chipset on a motherboard.) In desiring to rename controls, I assumed that the AC '97 multichannel driver control names represented an ALSA standard. Actually I don't know how other drivers name their multichannel controls. (The AC '97 driver generically uses "Master" playback to control the front channel pin attenuation, and "PCM" playback to control multichannel DAC levels into the mixer. "Surround", "Center" and "LFE" playback controls adjust pin attenuation for the respective channels.) The AD1986/AD1986A CODECs are at variance with the AC '97 standard, causing "Master" playback to control pin attenuation for all channels, "PCM" playback to control only the front channel DAC levels, and "Surround", "Center" and "LFE" playback controls to affect DAC levels for their respective channels. Hence my original reasoning that these control names are inappropriate. (Other AD AC '97 multichannel CODECs are even less intuitive regarding their control usage, but in the interest of brevity I'll save that discussion for later.) Questions: What is the function of playback controls "Master" and "PCM" for multichannel CODECs driven by modules other than snd_ac97_codec? Which control controls the front channels only, and which controls all channels? What is the function of playback controls with names such as "Surround", "Center", and "LFE"? Does ALSA need to standardize mixer control names, or should we continue to use whatever names are convenient for a given chipset/CODEC? What standard should we use? Randy Cushman ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
