MediaMuxer cannot create MP4 streams

Question

I am editing MP4 on Android using MediaExtractor to extract audio and video tracks and then create a new file using MediaMuxer. It is working fine. I can play the new MP4 on the phone (and other players), but I can not transfer this file on the Internet. When I stop MediaMuxer, it generates a log message

"The mp4 file will not be available for streaming."

I looked at the base code (MPEG4Writer.cpp) and it seems that the writer was having trouble calculating the required moov box size. He tries to guess using some heuristic if bit rate is not provided as a parameter for writing. The problem is that MediaMuxer does not provide the ability to set MPEG4Writer parameters. Am I missing something or am I stuck looking for another means of generating a file (or header)? Thanks.

Answer 1

In MPEG4Writer.cpp:

// The default MIN_MOOV_BOX_SIZE is set to 0.6% x 1MB / 2, // where 1MB is the common file size limit for MMS application. // The default MAX _MOOV_BOX_SIZE value is based on about 3 // minute video recording with a bit rate about 3 Mbps, because // statistics also show that most of the video captured are going // to be less than 3 minutes. 

This is a bad guess about how MediaMuxer can be used. We record a maximum of 15 seconds of high definition video, and MIN_MOOV_BOX_SIZE is too small. Therefore, to make the file available, I have to rewrite the file to move the moov header before mdat and fix some offsets. Here is my code. This is not great. Error paths are not handled correctly, and they make assumptions about the order of the boxes.

 public void fastPlay(String srcFile, String dstFile) { RandomAccessFile inFile = null; FileOutputStream outFile = null; try { inFile = new RandomAccessFile(new File(srcFile), "r"); outFile = new FileOutputStream(new File(dstFile)); int moovPos = 0; int mdatPos = 0; int moovSize = 0; int mdatSize = 0; byte[] boxSizeBuf = new byte[4]; byte[] pathBuf = new byte[4]; int boxSize; int dataSize; int bytesRead; int totalBytesRead = 0; int bytesWritten = 0; // First find the location and size of the moov and mdat boxes while (true) { try { boxSize = inFile.readInt(); bytesRead = inFile.read(pathBuf); if (bytesRead != 4) { Log.e(TAG, "Unexpected bytes read (path) " + bytesRead); break; } String pathRead = new String(pathBuf, "UTF-8"); dataSize = boxSize - 8; totalBytesRead += 8; if (pathRead.equals("moov")) { moovPos = totalBytesRead - 8; moovSize = boxSize; } else if (pathRead.equals("mdat")) { mdatPos = totalBytesRead - 8; mdatSize = boxSize; } totalBytesRead += inFile.skipBytes(dataSize); } catch (IOException e) { break; } } // Read the moov box into a buffer. This has to be patched up. Ug. inFile.seek(moovPos); byte[] moovBoxBuf = new byte[moovSize]; // This shouldn't be too big. bytesRead = inFile.read(moovBoxBuf); if (bytesRead != moovSize) { Log.e(TAG, "Couldn't read full moov box"); } // Now locate the stco boxes (chunk offset box) inside the moov box and patch // them up. This ain't purdy. int pos = 0; while (pos < moovBoxBuf.length - 4) { if (moovBoxBuf[pos] == 0x73 && moovBoxBuf[pos + 1] == 0x74 && moovBoxBuf[pos + 2] == 0x63 && moovBoxBuf[pos + 3] == 0x6f) { int stcoPos = pos - 4; int stcoSize = byteArrayToInt(moovBoxBuf, stcoPos); patchStco(moovBoxBuf, stcoSize, stcoPos, moovSize); } pos++; } inFile.seek(0); byte[] buf = new byte[(int) mdatPos]; // Write out everything before mdat inFile.read(buf); outFile.write(buf); // Write moov outFile.write(moovBoxBuf, 0, moovSize); // Write out mdat inFile.seek(mdatPos); bytesWritten = 0; while (bytesWritten < mdatSize) { int bytesRemaining = (int) mdatSize - bytesWritten; int bytesToRead = buf.length; if (bytesRemaining < bytesToRead) bytesToRead = bytesRemaining; bytesRead = inFile.read(buf, 0, bytesToRead); if (bytesRead > 0) { outFile.write(buf, 0, bytesRead); bytesWritten += bytesRead; } else { break; } } } catch (IOException e) { Log.e(TAG, e.getMessage()); } finally { try { if (outFile != null) outFile.close(); if (inFile != null) inFile.close(); } catch (IOException e) {} } } private void patchStco(byte[] buf, int size, int pos, int moovSize) { Log.e(TAG, "stco " + pos + " size " + size); // We are inserting the moov box before the mdat box so all of // offsets in the stco box need to be increased by the size of the moov box. The stco // box is variable in length. 4 byte size, 4 byte path, 4 byte version, 4 byte flags // followed by a variable number of chunk offsets. So subtract off 16 from size then // divide result by 4 to get the number of chunk offsets to patch up. int chunkOffsetCount = (size - 16) / 4; int chunkPos = pos + 16; for (int i = 0; i < chunkOffsetCount; i++) { int chunkOffset = byteArrayToInt(buf, chunkPos); int newChunkOffset = chunkOffset + moovSize; intToByteArray(newChunkOffset, buf, chunkPos); chunkPos += 4; } } public static int byteArrayToInt(byte[] b, int offset) { return b[offset + 3] & 0xFF | (b[offset + 2] & 0xFF) << 8 | (b[offset + 1] & 0xFF) << 16 | (b[offset] & 0xFF) << 24; } public void intToByteArray(int a, byte[] buf, int offset) { buf[offset] = (byte) ((a >> 24) & 0xFF); buf[offset + 1] = (byte) ((a >> 16) & 0xFF); buf[offset + 2] = (byte) ((a >> 8) & 0xFF); buf[offset + 3] = (byte) (a & 0xFF); } 

Answer 2

MediaMuxer does not currently create streaming MP4 files

You can try Intel INDE at https://software.intel.com/en-us/intel-inde and the Media Pack for Android, which is part of INDE, tutorials at https://software.intel.com/en-us/ articles / intel-inde-media-pack-for-android-tutorials . It has a sample that shows how to use a media package to create and stream files over a network.

For example, for streaming a camera, there is a sample CameraStreamerActivity.java

 public void onCreate(Bundle icicle) { capture = new CameraCapture(new AndroidMediaObjectFactory(getApplicationContext()), progressListener); parameters = new StreamingParameters(); parameters.Host = getString(R.string.streaming_server_default_ip); parameters.Port = Integer.parseInt(getString(R.string.streaming_server_default_port)); parameters.ApplicationName = getString(R.string.streaming_server_default_app); parameters.StreamName = getString(R.string.streaming_server_default_stream); parameters.isToPublishAudio = false; parameters.isToPublishVideo = true; } public void startStreaming() { configureMediaStreamFormat(); capture.setTargetVideoFormat(videoFormat); capture.setTargetAudioFormat(audioFormat); capture.setTargetConnection(prepareStreamingParams()); capture.start(); } 

In addition, there are simulations for streaming files or capturing and streaming gameplay.