Android，使用媒体解码器和libstreaming

Question

我对这个库有个问题

https://github.com/fyhertz/libstreaming

它允许通过无线发送相机的流媒体，它使用三种方式:两种与媒体解码器和一种与媒体录像机。我想要修改它，而且我必须只使用媒体解码器；然而，首先我尝试了库的示例2的代码，但我总是发现相同的错误:日志告诉我，设备可以使用媒体解码器，它设置编码器，当它测试解码器时，它会下降，缓冲区被-1填满。

这就是EncoderDebugger类中发生异常的方法，有没有人可以帮我？

private long decode(boolean withPrefix) {
    int n =3, i = 0, j = 0;
    long elapsed = 0, now = timestamp();
    int decInputIndex = 0, decOutputIndex = 0;
    ByteBuffer[] decInputBuffers = mDecoder.getInputBuffers();
    ByteBuffer[] decOutputBuffers = mDecoder.getOutputBuffers();
    BufferInfo info = new BufferInfo();

    while (elapsed<3000000) {

        // Feeds the decoder with a NAL unit
        if (i<NB_ENCODED) {

            decInputIndex = mDecoder.dequeueInputBuffer(1000000/FRAMERATE);
            if (decInputIndex>=0) {
                int l1 = decInputBuffers[decInputIndex].capacity();
                int l2 = mVideo[i].length;
                decInputBuffers[decInputIndex].clear();

                if ((withPrefix && hasPrefix(mVideo[i])) || (!withPrefix && !hasPrefix(mVideo[i]))) {

                    check(l1>=l2, "The decoder input buffer is not big enough (nal="+l2+", capacity="+l1+").");
                    decInputBuffers[decInputIndex].put(mVideo[i],0,mVideo[i].length);
                } else if (withPrefix && !hasPrefix(mVideo[i])) {

                    check(l1>=l2+4, "The decoder input buffer is not big enough (nal="+(l2+4)+", capacity="+l1+").");
                    decInputBuffers[decInputIndex].put(new byte[] {0,0,0,1});
                    decInputBuffers[decInputIndex].put(mVideo[i],0,mVideo[i].length);
                } else if (!withPrefix && hasPrefix(mVideo[i])) {

                    check(l1>=l2-4, "The decoder input buffer is not big enough (nal="+(l2-4)+", capacity="+l1+").");
                    decInputBuffers[decInputIndex].put(mVideo[i],4,mVideo[i].length-4);
                }

                mDecoder.queueInputBuffer(decInputIndex, 0, l2, timestamp(), 0);
                i++;
            } else {
                if (VERBOSE) Log.d(TAG,"No buffer available !7");
            }
        }

        // Tries to get a decoded image

        decOutputIndex = mDecoder.dequeueOutputBuffer(info, 1000000/FRAMERATE);
        if (decOutputIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
            decOutputBuffers = mDecoder.getOutputBuffers();
        } else if (decOutputIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
            mDecOutputFormat = mDecoder.getOutputFormat();
        } else if (decOutputIndex>=0) {
            if (n>2) {
                // We have successfully encoded and decoded an image !
                int length = info.size;
                mDecodedVideo[j] = new byte[length];
                decOutputBuffers[decOutputIndex].clear();
                decOutputBuffers[decOutputIndex].get(mDecodedVideo[j], 0, length);
                // Converts the decoded frame to NV21
                convertToNV21(j);
                if (j>=NB_DECODED-1) {

                    flushMediaCodec(mDecoder);
                    if (VERBOSE) Log.v(TAG, "Decoding "+n+" frames took "+elapsed/1000+" ms");
                    return elapsed;
                }
                j++;
            }
            mDecoder.releaseOutputBuffer(decOutputIndex, false);
            n++;
        }   
        elapsed = timestamp() - now;
    }

    throw new RuntimeException("The decoder did not decode anything.");

}

Answer 1

以下是我的建议：

(1)检查编码器和解码器的设置，确保匹配。例如，旋转和颜色格式是相同的。

(2)确保编码器生成的第一个包已经发送并推送到解码器。此包定义了视频流的基本设置。

(3)解码器通常缓存5-10帧。所以缓冲区中的数据在几百毫秒内是无效的。

(4)在启动解码器时，将表面设置为空。否则，输出缓冲区将被表面读取，并可能自动释放。