用Java构建了部分上传系统，但视频正在损坏

因此，我建立了一个图片和视频部分上传系统，在我们尝试压缩视频或用户尝试播放视频之前，该系统似乎工作正常。我发现写视频的字节并不像附加字节那么简单。。。我现在（稍微）熟悉原子（free、mov、mdat、uuid等）等概念，我想知道视频（它只是附加到新文件中的字节集合）为什么以及如何在写入所有字节的情况下仍无法识别原子

无论如何，这里有一些源代码：

服务器端我们有一个部分上载对象：

public class PartialUpload {
    private Integer partialUploadId;
    private String urlSuffix;
    private Date dateAdded;
    private Long expiresIn;
    private Long currentBytesMin;
    private Long currentBytesMax;
    private Long totalBytes;
    private Boolean complete;
    private String filename;

    //there are getters and setters which bind to a database entity below but these are the fields
}

在服务器端，我们也有以下方法来检查部分上传是否已经开始、正在继续或已经达到其总字节数

@RequestMapping(value = "/video_partial", method = RequestMethod.POST)
    public ResponseEntity<?> postVideoPartial(@RequestParam("name") String name, @RequestParam(name = "totalBytes") Long totalBytes) throws IOException {
        PartialUpload upload = new PartialUpload();
        upload.setUrlSuffix(upload.hashUrlSuffix()); // creates a url friendly hash
        Calendar expiry = Calendar.getInstance();
        upload.setDateAdded(expiry.getTime());
        expiry.add(Calendar.DAY_OF_MONTH, PARTIAL_UPLOAD_EXPIRY_TIME); // constant which is a day
        upload.setExpiresIn(expiry.getTimeInMillis() - Calendar.getInstance().getTimeInMillis());
        upload.setComplete(false);
        upload.setFilename(name);
        upload.setTotalBytes(totalBytes);
        partialUploadRepo.save(upload); //save this object to the database
        PartialUploadInitialDTO dto = new PartialUploadInitialDTO(); //initial DTO which contains the url suffix and the time it expires in
        dto.expiresIn = upload.getExpiresIn();
        dto.urlSuffix = upload.getUrlSuffix();
        return new ResponseEntity<>(dto, HttpStatus.ACCEPTED);
    }

//continuing the partial upload until complete
@RequestMapping(value = "/video_partial/{urlSuffix}", method = RequestMethod.POST)
    public ResponseEntity<?> postVideoPartial(@RequestBody byte[] partialBytes, @PathVariable("urlSuffix") String urlSuffix) throws IOException {
        try {
            PartialUpload upload = partialUploadRepo.getUploadByUrlSuffix(urlSuffix);
            if (!upload.isExpired()) {
                if (upload.getComplete() != null && upload.getComplete()) {
                    return new ResponseEntity<>("Upload already complete", HttpStatus.BAD_REQUEST);
                } else {

                    if (upload.getCurrentBytesMin() == null) { //tests if the very first chunk has been sent. If null, the chunk has yet to be sent
                        upload.setCurrentBytesMin(0L); //Tells the client to start at a 0 offset
                        upload.setCurrentBytesMax(START_BYTES_MAX); //Tells the client to upload bytes to the maximum... if there are fewer bytes than the maximum only the applicable bytes will be written
                        if (MediaHelper.initialFileWrite(partialBytes, upload, MediaType.VIDEO)) { //instantiates the file and writes bytes given the file does not yet exist
                            if (upload.getCurrentBytesMax() >= upload.getTotalBytes()) { // if the total bytes have been written
                                if (MediaHelper.moveFileToTempFolder(upload, MediaType.VIDEO)) { //moves the file for compression
                                    PartialUploadCompleteDTO completeDTO = new PartialUploadCompleteDTO();
                                    completeDTO.success = true;
                                    upload.setCurrentBytesMin(upload.getTotalBytes());
                                    upload.setCurrentBytesMax(upload.getTotalBytes());
                                    upload.setComplete(true);
                                    partialUploadRepo.save(upload); //saves that the upload has been completed
                                    return new ResponseEntity<>(completeDTO, HttpStatus.OK); //return success
                                } else {
                                    return new ResponseEntity<>("Couldn't Move File To Temp Folder", HttpStatus.INTERNAL_SERVER_ERROR);
                                }
                            } else {
                                //***************************************
                                PartialUploadInProgressDTO dto = new PartialUploadInProgressDTO(); //case where there are more chunks to upload and where I am receiving error
                                Calendar expiry = Calendar.getInstance();
                                expiry.setTime(upload.getDateAdded());
                                expiry.setTimeInMillis(expiry.getTimeInMillis() + upload.getExpiresIn());
                                dto.expirationDateTime = expiry.getTime();
                                dto.nextExpectedMin = upload.getCurrentBytesMax() + 1; //offset the next bytes by the last byte written + 1 MAY BE THE CAUSE OF THE ERRORS
                                dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin()); // offset the next max by the current max (which is the minimum) plus the interval number of bytes
                                if (dto.nextExpectedMax >= upload.getTotalBytes()) { //if the max overshoots the total bytes make the max the new total bytes
                                    dto.nextExpectedMax = upload.getTotalBytes();
                                }
                                upload.setCurrentBytesMin(dto.nextExpectedMin);
                                upload.setCurrentBytesMax(dto.nextExpectedMax);
                                partialUploadRepo.save(upload); // saves the next expected chunk
                               return new ResponseEntity<>(dto, HttpStatus.ACCEPTED);
                            }
                        } else {
                            return new ResponseEntity<>("Retry", HttpStatus.BAD_REQUEST);
                        }
                    } else {
                        //appends bytes to the already existing file
                        if (MediaHelper.appendBytesToFile(upload, partialBytes, MediaType.VIDEO)) {
                            if (upload.getCurrentBytesMax() >= upload.getTotalBytes()) { //test if complete (total bytes achieved)
                                if (MediaHelper.moveFileToTempFolder(upload, MediaType.VIDEO)) {
                                    PartialUploadCompleteDTO completeDTO = new PartialUploadCompleteDTO();
                                    completeDTO.success = true;
                                    upload.setCurrentBytesMin(upload.getTotalBytes());
                                    upload.setCurrentBytesMax(upload.getTotalBytes());
                                    upload.setComplete(true);
                                    partialUploadRepo.save(upload); //see above
                                    return new ResponseEntity<>(completeDTO, HttpStatus.OK);
                                } else {
                                    return new ResponseEntity<>("Couldn't Move File To Temp Folder", HttpStatus.INTERNAL_SERVER_ERROR);
                                }
                            } else {
                                PartialUploadInProgressDTO dto = new PartialUploadInProgressDTO();
                                Calendar expiry = Calendar.getInstance();
                                expiry.setTime(upload.getDateAdded());
                                expiry.setTimeInMillis(expiry.getTimeInMillis() + upload.getExpiresIn());
                                dto.expirationDateTime = expiry.getTime();
                                dto.nextExpectedMin = upload.getCurrentBytesMax() + 1;
                                dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin());
                                if (dto.nextExpectedMax >= upload.getTotalBytes()) {
                                    dto.nextExpectedMax = upload.getTotalBytes();
                                }
                                upload.setCurrentBytesMin(dto.nextExpectedMin);
                                upload.setCurrentBytesMax(dto.nextExpectedMax);
                                partialUploadRepo.save(upload);
                               return new ResponseEntity<>(dto, HttpStatus.ACCEPTED);
                            }
                        } else {
                            return new ResponseEntity<>("Retry", HttpStatus.BAD_REQUEST);
                        }
                    }
                }
            } else {
                return new ResponseEntity<>("Upload has expired", HttpStatus.BAD_REQUEST);
            }
        } catch(Exception e) {
            return new ResponseEntity<>("No File Exists At URL", HttpStatus.BAD_REQUEST);
        }
    }

在移动应用程序中，我使用QTFastStart的一个修改版本将moov原子移动到结构的前端（不需要，但这是一个临时解决方案）。否则moov原子就被破坏了。任何关于原子为什么在文件传输过程中被破坏的帮助都将不胜感激

下面是来自Android应用程序的更多源代码

if (currentMedia.getType() == VIDEO) {
                    try {
                        String newFileName = currentMedia.getPath(); //qualified media path
                        newFileName = newFileName.replaceAll("\\d+\\.mp4", "newFile.mp4"); //makes a temp mp4 for the current media. I tested with AtomicParsley and QTFastStart (PY) to make sure this wasn't the issue

                        File inFile = new File(currentMedia.getPath());
                        File outFile = new File(newFileName);
                        if (!outFile.exists()) {
                            outFile.createNewFile();
                        }
                        QtFastStart.fastStart(inFile, outFile); //moves the moov atom indices
                        outFile.renameTo(new File(currentMedia.getPath())); //makes the original file the moved file
                        file = new File(currentMedia.getPath());

                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (QtFastStart.MalformedFileException e) {
                        e.printStackTrace();
                    } catch (QtFastStart.UnsupportedFileException e) {
                        e.printStackTrace();
                    }
                } else {
                    file = new File(currentMedia.getPath());
                }
                //reads a total number of bytes from a file
                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
                    fileContent = Files.readAllBytes(file.toPath());
                } else {
                    fileContent = readFile(file);
                }

                if (currentMedia.getType() == IMAGE) {
                    mediaApiFactory.makeRequestStartImagePartialUpload(file.getName(), fileContent.length).start(null, initialResultListener);
                    pictureProgressText.setText("Uploading " + currentMedia.getName() + ".jpg");

                } else {
                    mediaApiFactory.makeRequestStartVideoPartialUpload(file.getName(), fileContent.length).start(null, initialResultListener);
                    pictureProgressText.setText("Uploading " + currentMedia.getName() + ".mp4");

                }

然后，我使用改装将视频/图像发送到服务器

然后我来处理回复

if (result != null && result.isSuccess()) {
                PartialUploadInitialDTO dto = result.getData();
                currentUrlSuffix = dto.urlSuffix;
                currentMinBytes = 0;
                currentMaxBytes = START_BYTES_MAX;
                chunks = new ArrayList<>();
                chunks.add(Arrays.copyOfRange(fileContent, (int)currentMinBytes, (int)currentMaxBytes));

                if (currentMedia.getType() == IMAGE) {
                    mediaApiFactory.makeRequestContinueImagePartialUpload(currentUrlSuffix, chunks.get(chunks.size() - 1)).start(null, intermediateResultListener);
                } else {
                    mediaApiFactory.makeRequestContinueVideoPartialUpload(currentUrlSuffix, chunks.get(chunks.size() - 1)).start(null, intermediateResultListener);
                }
            }

下面是到达服务器前后的平均atom树 运行QTQuick之前（但之后）：

之后（区块成功上传）

---

不管怎样，我为这篇冗长的文章感到抱歉。如果还需要什么，请询问，我会编辑此内容

所以我发现了问题，那是代码中的一个错误。当字节具有from和to值时，您不需要说明写入的最后一个字节，只需继续使用相同的数字即可。因此，以下是正确的：

dto.nextExpectedMin = upload.getCurrentBytesMax();
dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin());

无论我在哪里

dto.nextExpectedMin = upload.getCurrentBytesMax() + 1;
dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin());

以前

ftyp (24 bytes)
moov (15372 bytes)
mdat (67290713 bytes)

REM This is available upon request looks something like
ftyp (bytes)
moov (bytes)
NOTMDAT(bytes)

dto.nextExpectedMin = upload.getCurrentBytesMax();
dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin());

dto.nextExpectedMin = upload.getCurrentBytesMax() + 1;
dto.nextExpectedMax = upload.getCurrentBytesMax() + (upload.getCurrentBytesMax() - upload.getCurrentBytesMin());