使用libavfilter过滤视频时,巨大的内存泄漏 [英] Huge memory leak when filtering video with libavfilter
问题描述
我有一个相对简单的FFMPEG C程序,视频帧被馈送到该FFMPEG C程序,通过过滤器图形进行处理,然后发送到帧渲染器.
I have a relatively simple FFMPEG C program, to which a video frame is fed, processed via filter graph and sent to frame renderer.
以下是一些代码段:
/* Filter graph here */
char args[512];
enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB32 };
AVFilterGraph *filter_graph;
avfilter_register_all();
AVFilter *buffersrc = avfilter_get_by_name("buffer");
AVFilter *buffersink = avfilter_get_by_name("ffbuffersink");
AVBufferSinkParams *buffersink_params;
AVFilterInOut *outputs = avfilter_inout_alloc();
AVFilterInOut *inputs = avfilter_inout_alloc();
filter_graph = avfilter_graph_alloc();
snprintf(args, sizeof(args),
"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
av->codec_ctx->width, av->codec_ctx->height, av->codec_ctx->pix_fmt,
av->codec_ctx->time_base.num, av->codec_ctx->time_base.den,
av->codec_ctx->sample_aspect_ratio.num, av->codec_ctx->sample_aspect_ratio.den);
if(avfilter_graph_create_filter(&av->buffersrc_ctx, buffersrc, "in",args, NULL, filter_graph) < 0)
{
fprintf(stderr, "Cannot create buffer source\n");
return(0);
}
/* buffer video sink: to terminate the filter chain. */
buffersink_params = av_buffersink_params_alloc();
buffersink_params->pixel_fmts = pix_fmts;
if(avfilter_graph_create_filter(&av->buffersink_ctx, buffersink, "out",NULL, buffersink_params, filter_graph) < 0)
{
printf("Cannot create buffer sink\n");
return(HACKTV_ERROR);
}
/* Endpoints for the filter graph. */
outputs->name = av_strdup("in");
outputs->filter_ctx = av->buffersrc_ctx;
outputs->pad_idx = 0;
outputs->next = NULL;
inputs->name = av_strdup("out");
inputs->filter_ctx = av->buffersink_ctx;
inputs->pad_idx = 0;
inputs->next = NULL;
const char *filter_descr = "vflip";
if (avfilter_graph_parse_ptr(filter_graph, filter_descr, &inputs, &outputs, NULL) < 0)
{
printf("Cannot parse filter graph\n");
return(0);
}
if (avfilter_graph_config(filter_graph, NULL) < 0)
{
printf("Cannot configure filter graph\n");
return(0);
}
av_free(buffersink_params);
avfilter_inout_free(&inputs);
avfilter_inout_free(&outputs);
上面的代码在其他地方被调用:
The above code is called by these elsewhere:
av->frame_in->pts = av_frame_get_best_effort_timestamp(av->frame_in);
/* push the decoded frame into the filtergraph*/
if (av_buffersrc_add_frame(av->buffersrc_ctx, av->frame_in) < 0)
{
printf( "Error while feeding the filtdergraph\n");
break;
}
/* pull filtered pictures from the filtergraph */
if(av_buffersink_get_frame(av->buffersink_ctx, av->frame_out) < 0)
{
printf( "Error while sourcing the filtergraph\n");
break;
}
/* do stuff with frame */
现在,代码可以正常运行,并且视频以我期望的方式显示(出于测试目的而垂直翻转).
Now, the code works absolutely fine and the video comes out the way I expect it to (vertically flipped for testing purposes).
我遇到的最大问题是存在大量内存泄漏.高分辨率视频将在几秒钟内消耗2Gb,并使程序崩溃.我将泄漏追溯到这段代码:
The biggest issue I have is that there is a massive memory leak. An high res video will consume 2Gb in a matter of seconds and crash the program. I traced the leak to this piece of code:
/* push the decoded frame into the filtergraph*/
if (av_buffersrc_add_frame(av->buffersrc_ctx, av->frame_in) < 0)
如果我通过执行av->frame_out=av->frame_in;
绕过过滤器而没有将框架推入过滤器(并且显然没有从中拉出),则不会发生泄漏并且内存使用情况是稳定的.
If I bypass the filter by doing av->frame_out=av->frame_in;
without pushing the frame into it (and obviously not pulling from it), there is no leak and memory usage is stable.
现在,我对C还是很陌生,请保持柔和,但似乎我应该以某种方式清除buffersrc_ctx,但不知道如何清除.我查看了官方文档,但找不到任何东西.
Now, I am very new to C, so be gentle, but it seems like I should be clearing out the buffersrc_ctx somehow but no idea how. I've looked in official documentations but couldn't find anything.
有人可以建议吗?
推荐答案
发布后5分钟,看来我要做的就是在处理完每一帧后取消引用帧.
5 minutes after posting, looks like all I had to do was unreference frames after each one processed.
av_frame_unref(av->frame_in);
av_frame_unref(av->frame_out);
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