From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII; format=flowed Date: Tue, 11 Aug 2009 22:39:38 -0700 From: Roman Shaposhnik In-reply-to: To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-id: References: <38fa4d234fa7ff8613123fe9a6921943@quanstro.net> <13426df10908112014y49c5a89dpd616ce4529c1efe1@mail.gmail.com> Subject: Re: [9fans] audio standards -- too many to choose from Topicbox-Message-UUID: 43b38faa-ead5-11e9-9d60-3106f5b1d025 On Aug 11, 2009, at 10:15 PM, Tim Newsham wrote: > The simplicity is definitely attractive in its own right, > and I'll consider it. However, the devices do provide hardware > support for other formats which do require some work to convert. > mu-law and a-law come to mind.. In all my life doing multimedia I'm yet to come across real use of mu-law and a-law (except in legacy telephony which is really not multimedia, if you ask me). Russ is absolutely correct -- PCM is all there is for audio. Everything else is really more of a datalink issue. >> If you want a different device file into which you >> can write mp3 and other sound file formats, great: >> do it in user space, translating into the native hardware >> format. > > I agree wrt. "mp3". I'm considering the possibility of supporting > alaw, ulaw, pcm8, pcm16 in big/little and signed/unsigned formats, > and adpcm, using the hardware features... Here's a complete list of audio formats that one can make hardware either generate or accept. Where do you draw the line? $ ffmpeg -formats | grep DEA | egrep -v "wmav|vorbis|flac" DEA adpcm_4xm DEA adpcm_adx DEA adpcm_ct DEA adpcm_ea DEA adpcm_ima_dk3 DEA adpcm_ima_dk4 DEA adpcm_ima_qt DEA adpcm_ima_smjpeg DEA adpcm_ima_wav DEA adpcm_ima_ws DEA adpcm_ms DEA adpcm_sbpro_2 DEA adpcm_sbpro_3 DEA adpcm_sbpro_4 DEA adpcm_swf DEA adpcm_xa DEA adpcm_yamaha DEA g726 DEA gsm DEA mp2 DEA pcm_alaw DEA pcm_mulaw DEA pcm_s16be DEA pcm_s16le DEA pcm_s24be DEA pcm_s24daud DEA pcm_s24le DEA pcm_s32be DEA pcm_s32le DEA pcm_s8 DEA pcm_u16be DEA pcm_u16le DEA pcm_u24be DEA pcm_u24le DEA pcm_u32be DEA pcm_u32le DEA pcm_u8 DEA sonic DEA vorbis Thanks, Roman.