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• Mathematically lossless encoding and decoding of RGB24 image sequence

  25 avril 2013, par curryage

  I am trying to encode a RGB24 image sequence into a mathematically (not merely visually) lossless video. huffyuv was suggested on many online forums so I tried the following.

  ffmpeg -i frames\%06d.png  -vcodec huffyuv test.avi

  The resulting video was then decoded into frames again using ffmpeg

  ffmpeg -i test.avi outframes\%06d.png

  However, the input and output frames are not bit-by-bit identical as promised by huffyuv here. Any idea how I can accomplish this ? My eventual goal is to read the video file using OpenCV but I am willing to cross that bridge later once I obtain a losslessly encoded video file.

  This SO question mentions an attempt to obtain a lossless h264 avi and the summary of responses seems to indicate h264 cannot completely accomplish lossless encoding.

  Once again, to emphasize, I am interested in bit-by-bit identical encoding, not just visually similar. Large file sizes are acceptable as is large compression/decompression time.

• Trimming a video from URL without retrieving the whole file [on hold]

  27 mars 2016, par Shlomi Uziel

  I have implemented a service which is given a URL of a movie file and a start time indicator. Then I trim a length of a maximum of 1 minute from that period onwards.
  The process is done in a server by calling a command with ProcessBuilder :

  ffmpeg -accurate_seek -ss hh:mm:ss.sss -t 60 -i "url" -c:v copy -c:a copy outputPath

  However, some video files have their metadata in the end of the file.
  Since the videos are stored in a remote URL, I cannot manipulate them without retrieving them fully (e.g. by using -movflags +faststart).

  Is there a way to seek to the given point and trim the video without prefetching the whole file ?

• FFmpeg Streaming Video SpringBoot endpoint not show video duration in video players

  7 avril 2024, par lxluxo23

  it turns out that I've been working on a personal project just out of curiosity.
the main function is to stream video by first encoding it through ffmpeg
then playback said video from any other device
call it "plex" very very primitive

  


  although I achieve my goal which is to encode and send the video to the devices that make the request
this video is sent so to speak as a live broadcast.
I can only pause it, no forward or rewind, anyone have any idea what I am doing wrong or if I should take some other approach either in my service or controller ?

  


  I leave fragments of my code

  


  THE CONTROLLER

  


  @RestController&#xA;@RequestMapping("/api")&#xA;@Log4j2&#xA;public class StreamController {&#xA;&#xA;    @Autowired&#xA;    VideoStreamingService videoStreamingService;&#xA;&#xA;    @Autowired&#xA;    VideoService videoService;&#xA;&#xA;&#xA;    @GetMapping("/stream/{videoId}")&#xA;    public ResponseEntity<streamingresponsebody> livestream(@PathVariable Long videoId,@RequestParam(required = false)  String codec) {&#xA;        Video video = videoService.findVideoById(videoId);&#xA;        if (video != null) {&#xA;            Codec codecEnum = Codec.fromString(codec);&#xA;            return ResponseEntity.ok()&#xA;                    .contentType(MediaType.valueOf("video/mp4"))&#xA;                    .body(outputStream -> videoStreamingService.streamVideo(video.getPath(), outputStream,codecEnum));&#xA;        }&#xA;        return ResponseEntity.notFound().build();&#xA;    }&#xA;}&#xA;</streamingresponsebody>

  


  THE SERVICE

  


  @Service
public class VideoStreamingService {

    public void streamVideo(String videoPath, OutputStream outputStream, Codec codec) {

        FFmpeg ffmpeg = FFmpeg.atPath()
                .addArguments("-i", videoPath)
                .addArguments("-b:v", "5000k")
                .addArguments("-maxrate", "5000k")
                .addArguments("-bufsize", "10000k")
                .addArguments("-c:a", "aac")
                .addArguments("-b:a", "320k")
                .addArguments("-movflags", "frag_keyframe+empty_moov+faststart")
                .addOutput(PipeOutput.pumpTo(outputStream)
                        .setFormat("mp4"))
                .addArgument("-nostdin");
        if (codec == Codec.AMD) {
            ffmpeg.addArguments("-profile:v", "high");
        }
        ffmpeg.addArguments("-c:v", codec.getFfmpegArgument());
        ffmpeg.execute();
    }
}


  


  I have some enums to vary the encoding and use hardware acceleration or not.

  


  and here is an example from my player
the endpoint is the following

  


  http://localhost:8080/api/stream/2?codec=AMD
screenshot

  


  I'm not sure if there's someone with more knowledge in either FFmpeg or Spring who could help me with this minor issue, I would greatly appreciate it. I've included the URL of the repository in case anyone would like to review it when answering my question

  


  repo

  


  I tried changing the encoding format.
I tried copying the metadata from the original video.
I tried sending a custom header.
None of this has worked.

  


  I would like to achieve what is mentioned in many sites, which is when you load a video from the network, the player shows how much of that video you have in the local "buffer".