Recherche avancée

Sur d’autres sites (9179)

• ffmpeg output stereoscopic by duplicating a single input

  2 septembre 2018, par daedalus

  I want to have my desktop output video to be used with a VR headset so I need to convert the X11 output to left and right eye (but as a single video), it won’t be 3D since the left and right eye input is the same but thats fine. I think I am almost there but can’t get ffmpeg to treat a single source as two inputs. Here is what I have so far>

  ffmpeg -f x11grab -framerate 60  -video_size 1920x1080 -i :0.0 -i :0.0  -filter_complex "[0:v] scale=iw/2:ih/2, pad=2*iw:ih [left]; [1:v] scale=iw/3:ih/3, fade=out:300:30:alpha=1 [right]; [left][right] overlay=main_w/2:0 [out]" -vcodec libx264 -crf 16 -preset ultrafast sidebyside.mp4

  The command above should create a single output video with a duplicate of my display input for left and right eye on the left and right part of the video.

  The ffmpeg command above fails with

  :0.0 : Protocol not found
  Did you mean file::0.0 ?

  Thanks in advance

• ffmpeg for android, out of memory on decoding rotate mp4 file with openh264

  29 octobre 2018, par da que

  Version

  • ffmpeg : 4.0.2
  • openh264 : 1.8.0

  Problem

  I try to trim a .mp4 file which metadata info contains rotate info, but I failed with the error information.

  The file stream info :

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2018-10-09T09:40:53.000000Z
  
      location        : +39.8983+116.4145/
  
      location-eng    : +39.8983+116.4145/
  
      com.android.version: 6.0
  
    Duration: 00:00:10.56, start: 0.000000, bitrate: 8671 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 8563 kb/s, SAR 1:1 DAR 16:9, 30.01 fps, 30 tbr, 90k tbn, 180k tbc (default)
  
      Metadata:
  
        rotate          : 180
  
        creation_time   : 2018-10-09T09:40:53.000000Z
  
        handler_name    : VideoHandle
  
      Side data:
  
        displaymatrix: rotation of -180.00 degrees
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        creation_time   : 2018-10-09T09:40:53.000000Z
  
        handler_name    : SoundHandle

  ffmpeg cmd

  ffmpeg -y -i 1.mp4 -threads 4 -b:v 2000k -vcodec libopenh264 -acodec copy -ss 0 -t 3 -f mp4 -movflags faststart -strict -2 ./output.mp4

  result

  Error reinitializing filters!
  
  Failed to inject frame into filter network: Out of memory
  
  Error while processing the decoded data for stream #0:0

  Then I found this answer : ffmpeg-for-android-out-of-memory, after i added -noautorotate command to my cmd, the video is trimmed successful.

  If I use -vcodec copy instead of -vcodec libopenh264, the result also is ok, I wonder if there is a bug when libopenh264 decode with ffmpeg’s autorotate function.

  I wipe the video’s rotate info from metadata with -metadata:s:v:0 command, the newly video can be trimmed successful with the origin cmd :(

• How to grab ffmpeg's output as binary and write it to a file on the fly such that video players can play it in real time ?

  29 décembre 2022, par Mister Mystère

  I want to stream a RTSP-streaming device to a video player such as VLC but the catch is that, in between, the binary data needs to go through a custom high-speed serial link. I control what goes in this link from a C++ program.

  


  I was happily surprised to see that the following line allowed me to watch the RTSP stream by just opening "out.bin" from VLC which was a good lead for fast and efficient binary transmission of the stream :

  


  ffmpeg -i "rtsp://admin:password@X.X.X.X:554/h264Preview_01_main" -c:v copy -c:a copy -f mpegts out.bin


  


  I already wondered how ffmpeg manages to allow VLC to read that file, while itself writing to it at the same time. Turns out I was right to wonder, see below.

  


  I told myself I could make this command pipe its output to the standard output, and then in turn pipe the standard output to a file that I can read, (later, slice it, transmit the chunks and reconstruct it) and then write to an output file. However, this does not work :

  


  #include 
#include 
#include 

#define BUFSIZE 188 //MPEG-TS packet size

int main()
{
    char *cmd = (char*)"ffmpeg -i \"rtsp://admin:password@X.X.X.X:554/h264Preview_01_main\" -c:v copy -c:a copy -f mpegts pipe:1 -loglevel quiet";
    char buf[BUFSIZE];
    FILE *ptr, *file;

    file = fopen("./out.bin", "w");

    if (!file)
    {
        printf("Failed to open output file for writing, aborting");
       abort();
    }

    if ((ptr = popen(cmd, "r")) != NULL) {
       printf("Writing RTSP stream to file...");

       while (!kbhit())
       {
            if(fread(&buf, sizeof(char), BUFSIZE, ptr) != 0)
            {
               fwrite(buf, sizeof(char), BUFSIZE, file);
            }
            else
            {
                printf("No data\n");
            }
       }
       pclose(ptr);
    }
    else
    {
        printf("Failed to open pipe from ffmpeg command, aborting");
    }

    printf("End of program");

    fclose(file);
    return 0;
}


  


  Since VLC says "your input can't be opened" - whereas this works just fine :

  


  ffmpeg -i "rtsp://admin:password@X.X.X.X:554/h264Preview_01_main" -c:v copy -c:a copy -f mpegts pipe:1 -loglevel quiet > out.bin


  


  This is what ends up in the file after I close the program, versus the result of the command immediately above :


  


  The file is always 2kB regardless of how long I run the program : "No data" is shown repeatedly in the console output.

  


  Why doesn't it work ? If it is not just a bug, how can I grab the stream as binary at some point, and write it at the end to a file that VLC can read ?

  


  Update

  


  New code after applying Craig Estey's fix to my stupid mistake. The end result is that the MPEG-TS frames don't seem to shift anymore but the file writing stops partway into one of the first few frames (the console only shows a few ">" symbols and then stays silent, c.f. code).

  


  #include 
#include 
#include 

#define BUFSIZE 188                     // MPEG-TS packet size

int
main()
{
    char *cmd = (char *) "ffmpeg -i \"rtsp://127.0.0.1:8554/test.sdp\" -c:v copy -c:a copy -f mpegts pipe:1 -loglevel quiet";
    char buf[BUFSIZE];
    FILE *ptr,
    *file;

    file = fopen("./out.ts", "w");

    if (!file) {
        printf("Failed to open output file for writing, aborting");
        abort();
    }

    if ((ptr = popen(cmd, "r")) != NULL) {
        printf("Writing RTSP stream to file...");

        while(!kbhit()) {
            ssize_t rlen = fread(&buf, sizeof(char), BUFSIZE, ptr);
            if(rlen != 0)
            {
                printf(">");
                fwrite(buf, sizeof(char), rlen, file);
                fflush(file);
            }
        }
        pclose(ptr);
    }
    else {
        printf("Failed to open pipe from ffmpeg command, aborting");
    }

    printf("End of program");

    fclose(file);
    return 0;
}


  


  This can be tested on any computer with VLC and a webcam : open VLC, open capture device, capture mode directshow, (switch "play" for "stream"), next, display locally, select RTSP, Add, path=/test.sdp, next, transcoding=H264+MP3 (TS), replace rtsp ://:8554/ with rtsp ://127.0.0.1:8554/ in the generated command line, stream.

  


  To test that streaming is ok, you can just open a command terminal and enter "ffmpeg -i "rtsp ://127.0.0.1:8554/test.sdp" -c:v copy -c:a copy -f mpegts pipe:1 -loglevel quiet", the terminal should fill up with binary data.

  


  To test the program, just compile, run, and open out.ts after the program has run.