如何从AVFrame.data []和AVFrame.linesize []获取原始帧数据，而不指定像素格式？ [英] How to get raw frame data from AVFrame.data[] and AVFrame.linesize[] without specifying the pixel format?

问题描述

我得出一般的想法，根据视频（RGB或YUV）的像素格式来解释 frame.data [] 。但是有没有一种通常的方法来获取帧中的所有像素数据？我只想计算帧数据的哈希值，而不用解释它来显示图像。

根据AVFrame.h：

  uint8_t * AVFrame :: data [AV_NUM_DATA_POINTERS] 
  

  int AVFrame :: linesize [AV_NUM_DATA_POINTERS] 
  

对于视频，每个图片行的字节大小。

意味着如果我从 data [i] 中为 linesize [i] 字节提取，那么我将获得完整的像素信息关于框架？

解决方案

linesize [i] 包含

要获取整个缓冲区，请使用 avcodec中的函数.h

  / ** 
 *将像素数据从AVPicture复制到缓冲区，总是假设
 * linesize对齐1. * / 
 int avpicture_layout（const AVP icture * src，enum AVPixelFormat pix_fmt，
 int width，int height，
 unsigned char * dest，int dest_size）; 
  

使用

  int avpicture_get_size（枚举AVPixelFormat pix_fmt，int width，int height）; 
  

计算所需的缓冲区大小。

I get the general idea that the frame.data[] is interpreted depending on which pixel format is the video (RGB or YUV). But is there any general way to get all the pixel data from the frame? I just want to compute the hash of the frame data, without interpret it to display the image.

According to AVFrame.h:

uint8_t* AVFrame::data[AV_NUM_DATA_POINTERS]

pointer to the picture/channel planes.

int AVFrame::linesize[AV_NUM_DATA_POINTERS]

For video, size in bytes of each picture line.

Does this mean that if I just extract from data[i] for linesize[i] bytes then I get the full pixel information about the frame?

解决方案

linesize[i] contains stride for the i-th plane.

To obtain the whole buffer, use the function from avcodec.h

/**
 * Copy pixel data from an AVPicture into a buffer, always assume a
 * linesize alignment of 1. */   
int avpicture_layout(const AVPicture* src, enum AVPixelFormat pix_fmt,
                 int width, int height,
                 unsigned char *dest, int dest_size);

Use

int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);

to calculate the required buffer size.

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