Le ven. 22 nov. 2024 à 13:55, Mathieu Prevot <mathieu.pre...@gmail.com> a écrit :
> > Le mer. 20 nov. 2024 à 18:03, Mathieu Prevot <mathieu.pre...@gmail.com> a > écrit : > >> >> >> Le mar. 19 nov. 2024 à 00:39, Mathieu Prevot <mathieu.pre...@gmail.com> >> a écrit : >> >>> >>> >>> Le dim. 17 nov. 2024 à 20:57, Mathieu Prevot <mathieu.pre...@gmail.com> >>> a écrit : >>> >>>> Hello, >>>> >>>> I am using code, based on >>>> https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/hw_decode.c, >>>> but I am not transferring the decoded data to the host, I keep it on the >>>> device for later use with cuda code (my goal will be to use RGB 8-12 bits >>>> per channel data). >>>> >>>> I could not find a way to get the data format >>>> ((AVPixelFormat)frame->format translates to: "HW acceleration through CUDA. >>>> data[i] contain CUdeviceptr pointers exactly as for system memory frames.") >>>> >>>> I understand that I have two arrays: frame->data[0] and frame->data[1]. >>>> >>>> I would like to translate the data into a cuda native structure like: >>>> >>>> cudaPitchedPtr CUdeviceptr{}; >>>> CUdeviceptr.ptr = frame->data[0]; >>>> CUdeviceptr.ysize = frame->height; >>>> CUdeviceptr.xsize = frame->width; >>>> >>>> Which is probably wrong, since width==1920 height==1080 and should have >>>> colors or YUV data. >>>> >>>> How to get to know the data format (RGB, BGR, YUV, 8/10/12bits per >>>> channel etc) and the size of the array ? >>>> If it is not RGB8 (or 10-12), can I get that through some ffmpeg >>>> implementation, maybe with an nvdec based function ? >>>> What is the correct cuda-native data ? cudaPitchedPtr or something else >>>> ? >>>> frame->data[0] is uint8_t, but the array is probably something else in >>>> the general case; so what is it (as redundancy or extension of "what is the >>>> data format") ? >>>> >>> >>> It seems that frame->data[0] is the Y component of YUV, if not, one of >>> RGB channels, but I could not figure out what frame->data[1] is. >>> Can someone confirm ? >>> >> >> I got no answer from libav-user@, maybe is it a question for >> ffmpeg-devel@ (not subscribed, please cc) ? >> > > There seems to be no other data except that of `frame->data[0]`. > > I verified, there is nothing beyond `frame->data[0] + > frame->linesize[0]*frame->height`. > > frame->data[1] has another address but there is no data. > > frame->buf[0]->data and frame->extended_data both point to the same > address as frame->data[0]. > > no side_data or extended_buf, > > opaque_ref is NULL > > frame->ch_layout->order is AV_CHANNEL_ORDER_UNSPEC > > In the end, it comes down to this questions: > > 1. where are UV data of YUV when decoded by cuda ? Y is at frame->data[0]. > 2. frame->linesize[1] is set too, what is this for ? > Anyone ?
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