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 ? regards
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