Reply to thread

Message: <blockquote data-quote="tourettes" data-source="post: 616162" data-attributes="member: 10858">Re: AW: MP1 EVR Presenter/dshowhelper community developmentIn Short: audio needs to be resampled there is no magic workaround if you want to have perfect playback (no stuttering on 2 hour length movie on today's GPU / audio chip setup)The Whole Explanation:There are two different cases that we are talking about with the audio renderer experiments I'm doing. They are both requiring the audio to be decoded and resampled (time stretching, no pitch alteration) and Reclock is as well doing both of those:1) minor reference clock rate correction - This is required since GPU and audio chip don't share any common crystal for their clock signal sources. Not even modern GPUs that have audio support (don't ask me why... most likely to cut some costs as they buy the audio chips from different supplier?). When you have two different clock sources there will be always drifting in the A/V. And after enough drifting has happened one video frame needs to be dropped or presented twice (you cannot resample video <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />)2) non 1:1 (1:2, 1:3) matching playback - in short, playing 23.976 material on 25 display or using a PAL speed down to slow down the DVD etc approx 5% to get to the real playback speed (us europeans have faster brains and can process movies in shorter time than US fellows <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite8" alt=":D" title="Big Grin    :D" loading="lazy" data-shortname=":D" />).Both of those cases require audio to be decoded and resampled. I see no benefit of trying to re-encode the audio again. It will be enough to decode the audio, resample it and then pass it to the HDMI (8-channel available) as PCM. Encoding will lower the quality (unless using TrueHD or that other lossless format which I forget... we don't want to pay lisencing for the encoding as well) and cause more CPU to be used.Is it bitstream compatible? No it isn't. It wont be unless GPUs start to have only single clock chip to be shared with audio and video. And in that case the 1st case is not valid anymore and the 2nd should be fixed by a buying a proper tv/beamer.</blockquote>

Verification