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 frameavcodec_decode_video2(codecCtx, decodedFrame, &frameFinished,&packet);// Did we get a video frame?if(frameFinished) {// Convert the image from its native format to RGBAsws_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 bufferif (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 displayANativeWindow_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 frameavcodec_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,