Chiebot-Mirror/FFmpeg - FFmpeg - Gitea: Git with a cup of tea

Author	SHA1	Message	Date
Philip Langdale	d20df2601f	avcodec/nvenc: De-compensate aspect ratio compensation of DVD-like content. For reasons we are not privy to, nvidia decided that the nvenc encoder should apply aspect ratio compensation to 'DVD like' content, assuming that the content is not bt.601 compliant, but needs to be bt.601 compliant. In this context, that means that they make the following, questionable, assumptions: 1) If the input dimensions are 720x480 or 720x576, assume the content has an active area of 704x480 or 704x576. 2) Assume that whatever the input sample aspect ratio is, it does not account for the difference between 'physical' and 'active' dimensions. From, these assumptions, they then conclude that they can 'help', by adjusting the sample aspect ratio by a factor of 45/44. And indeed, if you wanted to display only the 704 wide active area with the same aspect ratio as the full 720 wide image - this would be the correct adjustment factor, but what if you don't? And more importantly, what if you're used to ffmpeg not making this kind of adjustment at encode time - because none of the other encoders do this! And, what if you had already accounted for bt.601 and your input had the correct attributes? Well, it's going to apply the compensation anyway! So, if you take some content, and feed it through nvenc repeatedly, it will keep scaling the aspect ratio every time, stretching your video out more and more and more. So, clearly, regardless of whether you want to apply bt.601 aspect ratio adjustments or not, this is not the way to do it. With any other ffmpeg encoder, you would do it as part of defining your input paramters or do the adjustment at playback time, and there's no reason by nvenc should be any different. This change adds some logic to undo the compensation that nvenc would otherwise do. nvidia engineers have told us that they will work to make this compensation mechanism optional in a future release of the nvenc SDK. At that point, we can adapt accordingly. Signed-off-by: Philip Langdale <philipl@overt.org> Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Timo Rothenpieler	fb34c580bb	avcodec/nvenc: Handle non-square pixel aspect ratios Reviewed-by: Philip Langdale <philipl@overt.org> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Timo Rothenpieler	914fd42b8a	avcodec/nvenc: Fix b-frame parameter handling This should behave similar to x264 and other encoders, as it handles a gop_size of 0 as Intra-Only, while it's still possible to control how many B-Frames it inserts. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Philip Langdale	ff0c559329	nvenc: Propagate desired number of reference frames. Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
agathah	dac91bb4c3	avcodec/nvenc: set repeatSPSPPS flag for streaming Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Timo Rothenpieler	bc3f76779b	avcodec/nvenc: Add support for nvenc api version 5 Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
agathah	72c61c272c	avcodec/nvenc: fix b frame settings Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Timo Rothenpieler	1efdb0a43f	avcodec/nvenc: Remove special cases for cygwin Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago
Timo Rothenpieler	2a428db5e2	avcodec: Add NVENC encoder Signed-off-by: Michael Niedermayer <michaelni@gmx.at>	10 years ago