当前位置：首页 > news >正文

ffmpeg在android上输出滑屏问题处理

news 来源：原创 2024/5/12 4:10:25

ffmpeg部分机器上有花屏的问题

原代码例如以下:

while(av_read_frame(formatCtx, &packet)>=0 && !_stop && NULL!=window && bInit) {
		// Is this a packet from the video stream?
		if(packet.stream_index==videoStream) {
			// Decode video frame
			avcodec_decode_video2(codecCtx, decodedFrame, &frameFinished,
			   &packet);
			// Did we get a video frame?
			if(frameFinished) {
				// Convert the image from its native format to RGBA
				sws_scale
				(
					sws_ctx,
					(uint8_t const * const *)decodedFrame->data,
					decodedFrame->linesize,
					0,
					codecCtx->height,
					frameRGBA->data,
					frameRGBA->linesize
				);

				if(packet.dts == AV_NOPTS_VALUE
						 && decodedFrame->opaque && *(uint64_t*)decodedFrame->opaque != AV_NOPTS_VALUE)
				{
					pts = *(uint64_t *)decodedFrame->opaque;
					LOGD("pst1: %d",pts);
				}
				else if(packet.dts != AV_NOPTS_VALUE) {
				  pts = packet.dts;
				  LOGD("pst2: %d",pts);
				} else {
				  pts = 0;
				  LOGD("pst3: %d",pts);
				}
				//pts = av_q2d(codecCtx->time_base) * 1000000.0 * i * 2;
				pts *= 1000;
				//LOGD("debug %d,%d,%f",pts, (long)(av_q2d(codecCtx->time_base) * 1000000.0 * i * 2), av_q2d(codecCtx->time_base));
				if(0 == pts || 0 == baseTime)
				{
					baseTime = av_gettime() - pts;
					LOGD("BASETIME: %d",baseTime);
				}else{
					waitTime = (baseTime + pts) - av_gettime();
					LOGD("WAITTIME: %d, %d",waitTime,pts);
				}

				//waitTime = (av_q2d(codecCtx->time_base) * 1000.0 - 0.0) * 1000;
				if(waitTime>0)
					usleep(waitTime);
				if(!_stop)
				{
					synchronized(lockWindow)
					{
						if(!_stop && NULL!=window)
						{
							// lock the window buffer
							if (ANativeWindow_lock(pWin, &windowBuffer, NULL) < 0) {
								LOGE("cannot lock window");
							} else {
								// draw the frame on buffer
								//LOGD("copy buffer %d:%d:%d", width, height, width*height*RGB_SIZE);
								//LOGD("window buffer: %d:%d:%d", windowBuffer.width, windowBuffer.height, windowBuffer.stride);
								memcpy(windowBuffer.bits, buffer,  width * height * RGB_SIZE);
								// unlock the window buffer and post it to display
								ANativeWindow_unlockAndPost(pWin);
								// count number of frames
								++i;
							}
						}
					}
				}
			}
		}

细致分析后发现部分分辨率又可以正常展示,感觉是宽度错位导致的,分析例如以下:

ORG: 176 * 144 F
X2: 352 288 O
X3: 528 432 F
X4: 704 576 O
X6: 1056 * O

X1.1 193 158 F
X1.2 211 172 F
X1.5 264 216 F

X0.5 88 72 F

X2?

: 352 290 O
X2?: 352 600 O
X2?: 352 720 O
X4?: 704 720 O
X6?: 1056 720 O

1280 ---1312
1056
1184
1248 ok

发现分辨率依照%64+32对齐, 感觉是内存对齐造成的, 查看ANativeWindow_Buffer例如以下

typedef struct ANativeWindow_Buffer {
    // The number of pixels that are show horizontally.
    int32_t width;

    // The number of pixels that are shown vertically.
    int32_t height;

    // The number of *pixels* that a line in the buffer takes in
    // memory.  This may be >= width.
    int32_t stride;

    // The format of the buffer.  One of WINDOW_FORMAT_*
    int32_t format;

    // The actual bits.
    void* bits;
    
    // Do not touch.
    uint32_t reserved[6];
} ANativeWindow_Buffer;

输出stride和width的日志发现,假设正常显示则stride==width, 通过凝视能够看出应该是内存对齐问题导致的,调整代码:

if(packet.stream_index==videoStream) {
			// Decode video frame
			avcodec_decode_video2(codecCtx, decodedFrame, &frameFinished,
			   &packet);
			// Did we get a video frame?

if(frameFinished) { // Convert the image from its native format to RGBA sws_scale ( sws_ctx, (uint8_t const * const *)decodedFrame->data, decodedFrame->linesize, 0, codecCtx->height, frameRGBA->data, frameRGBA->linesize ); if(packet.dts == AV_NOPTS_VALUE && decodedFrame->opaque && *(uint64_t*)decodedFrame->opaque != AV_NOPTS_VALUE) { pts = *(uint64_t *)decodedFrame->opaque; LOGD("pst1: %d",pts); } else if(packet.dts != AV_NOPTS_VALUE) { pts = packet.dts; LOGD("pst2: %d",pts); } else { pts = 0; LOGD("pst3: %d",pts); } //pts = av_q2d(codecCtx->time_base) * 1000000.0 * i * 2; pts *= 1000; //LOGD("debug %d,%d,%f",pts, (long)(av_q2d(codecCtx->time_base) * 1000000.0 * i * 2), av_q2d(codecCtx->time_base)); if(0 == pts || 0 == baseTime) { baseTime = av_gettime() - pts; LOGD("BASETIME: %d",baseTime); }else{ waitTime = (baseTime + pts) - av_gettime(); LOGD("WAITTIME: %d, %d",waitTime,pts); } //waitTime = (av_q2d(codecCtx->time_base) * 1000.0 - 0.0) * 1000; if(waitTime>0) usleep(waitTime); if(!_stop) { synchronized(lockWindow) { if(!_stop && NULL!=window) { // lock the window buffer if (ANativeWindow_lock(pWin, &windowBuffer, NULL) < 0) { LOGE("cannot lock window"); } else { // draw the frame on buffer //LOGD("copy buffer %d:%d:%d", width, height, width*height*RGB_SIZE); //LOGD("window buffer: %d:%d:%d", windowBuffer.width, windowBuffer.height, windowBuffer.stride); //memcpy(windowBuffer.bits, buffer, width * height * RGB_SIZE); if(windowBuffer.width >= windowBuffer.stride){ memcpy(windowBuffer.bits, buffer, width * height * RGB_SIZE); }else{ //skip stride-width 跳过padding部分内存 for(int i=0;i<height;++i) memcpy(windowBuffer.bits + windowBuffer.stride * i * RGB_SIZE , buffer + width * i * RGB_SIZE , width * RGB_SIZE); } // unlock the window buffer and post it to display ANativeWindow_unlockAndPost(pWin); // count number of frames ++i; } } } } } }

通过行拷贝方式,跳过后面对齐部分的内存,

解决这个问题,