Question

我正在使用KxMovie：https://github.com/kolyvan/kxmovie

似乎停止流并关闭视图控制器应该使用[暂停]; 但是，我正在尝试接收来自gstreamer版本的流，如果流未正确关闭（它刚刚悬挂），则会出现内存泄漏。

所以，只是[暂停]对我来说不是一个选择。

我正在尝试在KxMovie解码器中使用[closeFile]：

-(void) closeFile
{

[self closeAudioStream];
[self closeVideoStream];
[self closeSubtitleStream];

_videoStreams = nil;
_audioStreams = nil;
_subtitleStreams = nil;

     if (_formatCtx) {
         _formatCtx->interrupt_callback.opaque = NULL;
         _formatCtx->interrupt_callback.callback = NULL;
         avformat_close_input(&_formatCtx);
         _formatCtx = NULL;
     }
}

但是，在[closeFile]发出avformat_close_input后，我通常会从av_read_frame获得EXC_BAD_ACCESS。

有人可以给我一些关于如何使用ffmpeg彻底关闭RTSP流的建议吗？

谢谢！

Answer 1

需要使用中断回调来中断av_read_frame

        _formatCtx->interrupt_callback.opaque
        _formatCtx->interrupt_callback.callback

等待调用回调并返回非零值。在回调返回一个中断值后，可以安全地调用av_close_input（在关闭所有使用的编解码器之后）。

Answer 2

以下代码段位于Objective-C中，而实现文件.m用于处理RTSP内容（RTSPProvider）的对象。

已使用Xcode版本10.1（10B61）和迄今为止最新的FFmpeg版本的手动构建的FFmpeg版本（4.2.1 / 15.10.2019）进行了测试。

是否需要构建脚本配置和/或使用的库版本（只需询问）。

我遇到了与OP相同的问题，但是无法使用他的解决方案。

完整版本与我使用的中断回调是：

    int interruptCallBack(void *ctx){
    RTSPProviderObject *whyFFmpeg = (__bridge RTSPProviderObject*)ctx;
    NSLog(@"What is this!");
    if(whyFFmpeg.whatIsHappeningSTR) {
        return 1;
    } else {
        return 0;
    }
}

返回值1应该已经中断av_read_frame()并退出了，而就我目前的理解而言却没有崩溃。

它仍然崩溃。我的解决方案是让av_read_frame()完成读取并终止会话上下文，该会话上下文将被释放并且不再允许任何读取。这很容易，因为我在释放RTSPProviderObject并没有完成阅读时遇到了这个问题。

最终用法是：

[self.rtspProvider cleanup];
self.rtspProvider = nil;

下面是完整的代码段：

#import "Don't forget the required ffmpeg headers or header file"

int interruptCallBack(void *ctx){
    RTSPProviderObject *whyFFmpeg = (__bridge RTSPProviderObject*)ctx;
    NSLog(@"What is this!");
    if(whyFFmpeg.whatIsHappeningSTR) {
        return 1;
    } else {
        return 0;
    }
}

@interface RTSPProviderObject ()
@property (nonatomic, assign) AVFormatContext *sessionContext;
@property (nonatomic, assign) NSString *whatIsHappeningSTR;
@property (nonatomic, assign) AVDictionary *sessionOptions;
@property (nonatomic, assign) BOOL usesTcp;
@property (nonatomic, assign) BOOL isInputStreamOpen;
@property (nonatomic, strong) NSLock *audioPacketQueueLock;
@property (nonatomic, strong) NSLock *packetQueueLock;
@property (nonatomic, strong, readwrite) NSMutableArray *audioPacketQueue;
@property (nonatomic, assign) int selectedVideoStreamIndex;
@property (nonatomic, assign) int selectedAudioStreamIndex;
@end


@implementation RTSPProviderObject

- (id _Nullable)init
{
    self = [super init];
    if (!self)
    {
        return nil;
    }

    self.sessionContext = NULL;
    self.sessionContext = avformat_alloc_context();

    AVFormatContext *pFormatCtx = self.sessionContext;
    if (!pFormatCtx)
    {
        // Error handling code...
    }

    // MUST be called before avformat_open_input().
    av_dict_free(&_sessionOptions);

    self.sessionOptions = 0;
    if (self.usesTcp)
    {
        // "rtsp_transport" - Set RTSP transport protocols.
        // Allowed are: udp_multicast, tcp, udp, http.

        av_dict_set(&_sessionOptions, "rtsp_transport", "tcp", 0);
    }   

    // Open an input stream and read the header with the demuxer options.
    // rtspURL - connection url to your remote ip camera which supports RTSP 2.0.
    if (avformat_open_input(&pFormatCtx, rtspURL.UTF8String, NULL, &_sessionOptions) != 0)
    {
        self.isInputStreamOpen = NO;
       // Error handling code...
    }

    self.isInputStreamOpen = YES;

    // user-supplied AVFormatContext pFormatCtx might have been modified.
    self.sessionContext = pFormatCtx;
    pFormatCtx->interrupt_callback.callback = interruptCallBack;
    pFormatCtx->interrupt_callback.opaque = (__bridge void *)(self);

    // ... Other needed but currently not relevant code for codec/stream and other setup.
}

- (BOOL)prepareNextFrame
{
    NSLog(@"%s", __PRETTY_FUNCTION__);

    int isVideoFrameAvailable = 0;

    // The session context is needed to provide frame data. Frame data is provided for video and audio.
    // av_read_frame reads from pFormatCtx.
    AVFormatContext *pFormatCtx = self.sessionContext;
    if (!pFormatCtx) { return NO; }

    // Audio packet access is forbidden.
    [self.packetQueueLock lock];
    BOOL readResult = YES;
    // Calling av_read_frame while it is reading causes a bad_exception.
    // We read frames as long as the session context cotains frames to be read and cosumed (usually one).
    while (!isVideoFrameAvailable && self.isInputStreamOpen && readResult) {
        if (packet.buf == nil && self.whatIsHappeningSTR) {
            [self.packetQueueLock unlock];
            return NO;
        }
        NSLog(@"New frame will be read.");
        if (self.shouldTerminateStreams) {
            [self terminate];
            [self.packetQueueLock unlock];
            return NO;
        }
        readResult = av_read_frame(pFormatCtx, &packet) >=0;
        // Video packet data decoding.
        // We need to make sure that the frame video data which is consumed matches the user selected stream.
        if(packet.stream_index == self.selectedVideoStreamId) {

            // DEPRECIATED:
            // avcodec_decode_video2(self.videoCodecContext, self.rawFrameData, &isVideoFrameAvailable, &packet);
            // Replaced by this new implememtation. Read more: https://blogs.gentoo.org/lu_zero/2016/03/29/new-avcodec-api/
            // *
            // We need the video context to decode video data.
            AVCodecContext *videoContext = self.videoCodecContext;
            if (!videoContext && videoContext->codec_type == AVMEDIA_TYPE_VIDEO) { isVideoFrameAvailable = 1; }

            int ret;
            // Supply raw packet data as input to a decoder.
            ret = avcodec_send_packet(videoContext, &packet);

            if (ret < 0)
            {
                NSLog(@"codec: sending video packet failed");
                [self.packetQueueLock unlock];
                return NO;
            }

            // Return decoded output data from a decoder.
            ret = avcodec_receive_frame(videoContext, self.rawFrameData);
            if (isVideoFrameAvailable < 0 && isVideoFrameAvailable != AVERROR(EAGAIN) && isVideoFrameAvailable != AVERROR_EOF)
            {
                [self.packetQueueLock unlock];
                return NO;
            }

            if (ret >= 0) { isVideoFrameAvailable = 1; }
            // *
        } else {
            // avcodec_decode_video2 unreference all the buffers referenced by self.rawFrameData and reset the frame fields.
            // We must do this manually if we don't use the video frame or we will leak the frame data.
            av_frame_unref(self.rawFrameData);
            isVideoFrameAvailable = 1;
        }

        // Audio packet data consumption.
        // We need to make sure that the frame audio data which will be consumed matches the user selected stream.
        if (packet.stream_index == self.selectedAudioStreamIndex) {

            [self.audioPacketQueueLock lock];

            [self.audioPacketQueue addObject:[NSMutableData dataWithBytes:&packet length:sizeof(packet)]];

            [self.audioPacketQueueLock unlock];
        }

    }

    [self.packetQueueLock unlock];

    return isVideoFrameAvailable!=0;
}

- (void)cleanup
{
    NSLog(@"%s", __PRETTY_FUNCTION__);
    self.shouldTerminateStreams = YES;
    self.whatIsHappeningSTR = @"";
}

- (void)terminate
{
    avformat_close_input(&_sessionContext);
}

@end

希望这对任何人都有帮助。感谢您的阅读和贡献。

Answer 3

我也对此感到困惑，我不太了解你的解决方案。

我在下面修好了，你能提一些建议吗？

_dispatchQueue与asyncDecodeFrames工作的队列相同。

- (void)unSetup {

    _buffered = NO;
    _interrupted = YES;

    dispatch_async(_dispatchQueue, ^{
        if (_decoder) {

            [self pause];
            [self freeBufferedFrames];

            if (_moviePosition == 0 || _decoder.isEOF)
                [gHistory removeObjectForKey:_decoder.path];
            else if (!_decoder.isNetwork)
                [gHistory setValue:[NSNumber numberWithFloat:_moviePosition]
                            forKey:_decoder.path];

            [_decoder closeFile];
        }
    });

}

FFMPEG：干净地关闭RTSP流 - avformat_close_input上的av_read_frame崩溃

3 个答案: