[FFmpeg-user] How to solve flickering image / corrupted image

[whoami Jils]

 i am writing simple video player in android , I looked at SDL Side, and
there is no issue in rendering. But from ffmpeg side, i have a question.

What i am trying to achieve is :


1) Get the complete frame from ffmpeg,
2) Update into texture & render.

3) I have hard coded the Height/Width value ,1280, 720, as i am getting the
same from streaming server. [ i don't depend on it from context, as it does
not provide initially unless i retrieve some packet ]


Issue:

Flickering image.

I am not sure if there are any buffer issues i need to consider from ffmpeg
side?


Kindly advice.

Here is my code:

av_register_all();

if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
LOGD ( "Could not initialize SDL - %s\n", SDL_GetError());
exit(1);
}


if (avformat_open_input(&pFormatCtx, "rtsp://<IP>:Port", NULL, NULL) != 0)
return -1; // Couldn't open file

// Retrieve stream information
if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
return -1; // Couldn't find stream information


// Find the first video stream
videoStream = -1;
for (i = 0; i < pFormatCtx->nb_streams; i++)
if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
videoStream = i;
break;
}
if (videoStream == -1)
return -1;

// Get a pointer to the codec context for the video stream
pCodecCtx = pFormatCtx->streams[videoStream]->codec;

// Find the decoder for the video stream
pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (pCodec == NULL) {
LOGD ("Unsupported codec!\n");
return -1; // Codec not found
}

// Open codec
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
return -1; // Could not open codec

// Allocate video frame
pFrame = avcodec_alloc_frame();


screen = SDL_CreateWindow ("Testing..",SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED, 1280, 720, \
SDL_WINDOW_SHOWN|SDL_WINDOW_ALLOW_HIGHDPI );
if (!screen) {
fprintf(stderr, "SDL: could not set video mode - exiting\n");
exit(1);
}

renderer = SDL_CreateRenderer (screen, -1, SDL_RENDERER_ACCELERATED|
SDL_RENDERER_TARGETTEXTURE);
bmp = SDL_CreateTexture (renderer, SDL_PIXELFORMAT_YV12,
SDL_TEXTUREACCESS_STREAMING,1280, 720);

i = 0;
while (av_read_frame(pFormatCtx, &packet) >= 0) {
if (packet.stream_index == videoStream) {
avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);

if (frameFinished) {
SDL_UpdateYUVTexture(bmp, NULL, pFrame->data[0], pFrame->linesize[0], \
pFrame->data[1], pFrame->linesize[1], \
pFrame->data[2], pFrame->linesize[2]);

}
}

av_free_packet(&packet);
SDL_RenderClear(renderer);
retcopy = SDL_RenderCopy(renderer, bmp, NULL, NULL);
SDL_RenderPresent(renderer);

SDL_PollEvent(&event);
switch (event.type) {
case SDL_QUIT:
SDL_Quit();
exit(0);
break;
case SDL_KEYDOWN:
SDL_Quit ();
exit (0);
default:
break;
}

}

av_free(pFrame);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}