OSError: exception: access violation writing and reading

OSError: exception: access violation writing 0x0000000000000000

原因：pFormatCtx 么有分配内存

//pFormatCtx = NULL;
//pFormatCtx = avformat_alloc_context();
////aviobuffer = (unsigned char *)av_malloc(1512);
//AVIOContext *avio2 = avio_alloc_context(aviobuffer, 1512, 0, &deviceInfo, read_buffer, NULL, NULL);
//pFormatCtx->pb = avio2;
if (avformat_open_input(&pFormatCtx, NULL, NULL, NULL) != 0) {
printf("2Couldn't open input stream %d\n", cam_no);
//return -1;

}

正确做法：

                       pFormatCtx = NULL;
pFormatCtx = avformat_alloc_context();
//aviobuffer = (unsigned char *)av_malloc(1512);
AVIOContext *avio2 = avio_alloc_context(aviobuffer, 1512, 0, &deviceInfo, read_buffer, NULL, NULL);
pFormatCtx->pb = avio2;
if (avformat_open_input(&pFormatCtx, NULL, NULL, NULL) != 0) {
printf("2Couldn't open input stream %d\n", cam_no);
//return -1;
}

OSError: exception: access violation reading 0x0000000000000028

原因：avformat_open_input没有调用：

if (avformat_open_input(&pFormatCtx, NULL, NULL, NULL) != 0) {
printf("2Couldn't open input stream %d\n", cam_no);
//return -1;
}