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.mp4 playback too fast?
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<blockquote data-quote="mm1352000" data-source="post: 1153223" data-attributes="member: 82144"><p>Yes, that's currently true. However, it is not something that is fixed in stone. The output frame rate is configurable. Refer to:</p><p><a href="http://wiki.team-mediaportal.com/1_MEDIAPORTAL_1/141_Configuration/MediaPortal_Configuration/11_General/21_Dynamic_Refresh_Rate" target="_blank">http://wiki.team-mediaportal.com/1_MEDIAPORTAL_1/141_Configuration/MediaPortal_Configuration/11_General/21_Dynamic_Refresh_Rate</a></p><p></p><p></p><p>davidf has given you an excellent explanation of what the MPAR is doing and why. I don't think I can explain better, but maybe different words will help...</p><p></p><p>In an ideal world, best practise is to set the PC output frame rate to match the source (video file, DVD, whatever) fps. That way you get "perfect" video playback. When I say "perfect" I mean that no frames are dropped or repeated.</p><p></p><p>When you play a 23.976 fps music video on your setup, MediaPortal tries to adjust the PC output frame rate to 23.976 fps to match (as per the "ideal world" principle given above). <strong>This adjustment fails</strong> because your TV doesn't support the 23.976 fps refresh rate. MPAR does not change the refresh rate to 25 fps. Rather, that is the setting that your TV is using. What MPAR is trying to do is match the TV's actual refresh rate <strong>to give the best possible video quality</strong>. The trade-off for having better video quality is the increased audio "BPM" which you noticed.</p><p></p><p></p><p></p><p>This statement is not correct for the reasons that davidf already explained in his previous post.</p><p></p><p></p><p>This statement is partially correct and partially incorrect.</p><p></p><p>First, let's be clear. Based on what I saw in your log files, <strong>some</strong> of the music videos are 23.976 fps; others are 25 (50) fps. Note that 23.976 fps is not 24 fps. They are not the same thing, and the difference is significant.</p><p></p><p>Second: the NVidia renderer <strong>is</strong> "correctly outputting" the audio... however, the video output is slightly compromised. Compromised in that some frames will be displayed twice, which may be observed as a slightly jerks or micro-stutters in the video.</p><p></p><p>You could think of the situation this way...</p><p>It is impossible for you to get perfect video <strong>and </strong>audio output for 23.976 fps content because your TV doesn't support the 23.976 fps refresh rate.</p><p>You can only get perfection with video <strong>or</strong> audio.</p><p>Different renderers give you different trade-offs.</p><p>As explained above, the NVidia renderer compromises video quality in favour of audio quality.</p><p>MPAR does the opposite, compromising audio quality in favour of video quality.</p><p>You have to choose which compromise you will take.</p><p></p><p></p><p></p><p>Ultimately everything is your choice. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p>If you don't notice the loss in video quality when using the NVidia renderer then it is okay to use it... but be aware that there <strong>is </strong>a degradation.</p><p></p><p></p><p>As above: no dropped or repeated video frames.</p><p></p><p></p><p>Two final points.</p><p></p><p>1. This issue only affects content/sources when your TV doesn't support the content's refresh rate. In other words, 23.976 fps content is affected; 25 fps content is not. Currently we don't know for sure whether 24 fps content would be affected. However, if your TV is relatively modern it is likely that it supports 24 fps (for Blu-Rays).</p><p></p><p>2. On that same line of thinking: assuming that your TV <strong>does</strong> support 24 fps, davidf has recommended you try adjusting your MediaPortal dynamic refresh rate settings to use 24 fps instead of 23.976 fps. Why would you want to try that? Well, if successful, that adjustment would <strong>significantly</strong> reduce the "increased BPM" effect when using MPAR. So, you would get perfect video (ie. better than using NVidia) and 99.9% perfect audio. Note that the reason the adjustment is effective is that 24 fps is a closer match to 23.976 fps than 25 fps is:</p><p></p><p>100 x 23.976 / 25 fps = 95.904 % accurate matching</p><p>100 x 23.976 / 24 fps = 99.9 % accurate matching</p></blockquote><p></p>
[QUOTE="mm1352000, post: 1153223, member: 82144"] Yes, that's currently true. However, it is not something that is fixed in stone. The output frame rate is configurable. Refer to: [URL]http://wiki.team-mediaportal.com/1_MEDIAPORTAL_1/141_Configuration/MediaPortal_Configuration/11_General/21_Dynamic_Refresh_Rate[/URL] davidf has given you an excellent explanation of what the MPAR is doing and why. I don't think I can explain better, but maybe different words will help... In an ideal world, best practise is to set the PC output frame rate to match the source (video file, DVD, whatever) fps. That way you get "perfect" video playback. When I say "perfect" I mean that no frames are dropped or repeated. When you play a 23.976 fps music video on your setup, MediaPortal tries to adjust the PC output frame rate to 23.976 fps to match (as per the "ideal world" principle given above). [B]This adjustment fails[/B] because your TV doesn't support the 23.976 fps refresh rate. MPAR does not change the refresh rate to 25 fps. Rather, that is the setting that your TV is using. What MPAR is trying to do is match the TV's actual refresh rate [B]to give the best possible video quality[/B]. The trade-off for having better video quality is the increased audio "BPM" which you noticed. This statement is not correct for the reasons that davidf already explained in his previous post. This statement is partially correct and partially incorrect. First, let's be clear. Based on what I saw in your log files, [B]some[/B] of the music videos are 23.976 fps; others are 25 (50) fps. Note that 23.976 fps is not 24 fps. They are not the same thing, and the difference is significant. Second: the NVidia renderer [B]is[/B] "correctly outputting" the audio... however, the video output is slightly compromised. Compromised in that some frames will be displayed twice, which may be observed as a slightly jerks or micro-stutters in the video. You could think of the situation this way... It is impossible for you to get perfect video [B]and [/B]audio output for 23.976 fps content because your TV doesn't support the 23.976 fps refresh rate. You can only get perfection with video [B]or[/B] audio. Different renderers give you different trade-offs. As explained above, the NVidia renderer compromises video quality in favour of audio quality. MPAR does the opposite, compromising audio quality in favour of video quality. You have to choose which compromise you will take. Ultimately everything is your choice. :) If you don't notice the loss in video quality when using the NVidia renderer then it is okay to use it... but be aware that there [B]is [/B]a degradation. As above: no dropped or repeated video frames. Two final points. 1. This issue only affects content/sources when your TV doesn't support the content's refresh rate. In other words, 23.976 fps content is affected; 25 fps content is not. Currently we don't know for sure whether 24 fps content would be affected. However, if your TV is relatively modern it is likely that it supports 24 fps (for Blu-Rays). 2. On that same line of thinking: assuming that your TV [B]does[/B] support 24 fps, davidf has recommended you try adjusting your MediaPortal dynamic refresh rate settings to use 24 fps instead of 23.976 fps. Why would you want to try that? Well, if successful, that adjustment would [B]significantly[/B] reduce the "increased BPM" effect when using MPAR. So, you would get perfect video (ie. better than using NVidia) and 99.9% perfect audio. Note that the reason the adjustment is effective is that 24 fps is a closer match to 23.976 fps than 25 fps is: 100 x 23.976 / 25 fps = 95.904 % accurate matching 100 x 23.976 / 24 fps = 99.9 % accurate matching [/QUOTE]
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