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• How to extract time-accurate video segments with ffmpeg ?

  25 mai 2016, par Jim Miller

  This is not a particularly new question area around here, but I’ve tried what’s been suggested there without much luck. So, my story :

  I’ve got a hunk of 15 seconds of straight-from-the-camera.mov video out of which I want to extract a specific chunk, which I can identify by start time and stop time, in seconds. I started by trying to do what I’ll call a "copy extraction" : to get seconds 9 to 12,

  ffmpeg -i test.mov -vcodec copy -acodec copy -ss 9 -to 12 test-copy.mov

  This was a not-bad start, but there are some black frames at the beginning and end of the clip, which I can’t have — it has to be a clean edit from the original. So, I tried recoding the original into a new, trimmed clip :

  ffmpeg -i test.mov -ss 00:00:09 -t 00:00:03 test-out.mov

  This is better, but not quite : There are no longer any black frames at the beginning of the clip, but they’re still there at the end.

  After some more browsing and reading, I then suspected that the problem is that ffmpeg is having trouble finding the proper points because of a lack of keyframes in the original video. So I recoded the original video to (presumably) add keyframes, in a couple of different ways. Since I want to be able to pick video at boundaries of a second ("from 9 seconds to 12 seconds"), I tried, copying various suggestions around the web,

  ffmpeg -i test.mov -force_key_frames "expr:gte(t, n_forced)" test-forced.mp4

  and

  ffmpeg -i test.mov -g 1 test-g-inserted.mp4

  (I built these as mp4’s based on some comments about an mp4 container being needed to support the keyframe search, but I’m honestly just hacking here.) I then tried the extraction as before, but on these new videos that presumably now have keyframes in them. No luck — both seem to be about the same ; the start is OK but there are still black frames at the end. (FWIW, both test-forced.mp4 and test-g-inserted.mp4 also have trailing black frames.)

  So : I’m still stuck, and would like to not be. Any insights out there as to what I’m doing wrong ? I feel like I’m close, but I really need to get rid of those trailing black frames....

• avcodec/nvdec : Add support for decoding HEVC 4:4:4 content

  7 octobre 2018, par Philip Langdale

  avcodec/nvdec : Add support for decoding HEVC 4:4:4 content
  The latest generation video decoder on the Turing chips supports
  
  decoding HEVC 4:4:4. Supporting this is relatively straight-forward ;
  
  we need to account for the different chroma format and pick the
  
  right output and sw formats at the right times.
  There was one bug which was the hard-coded assumption that the
  
  first chroma plane would be half-height ; I fixed this to use the
  
  actual shift value on the plane.
  We also need to pass the SPS and PPS range extension flags.
  

  • [DH] libavcodec/hevcdec.c
  • [DH] libavcodec/nvdec.c
  • [DH] libavcodec/nvdec_hevc.c

• How to fix av_interleaved_write_frame() broken pipe error in php

  31 mars, par Adekunle Adeyeye

  I have an issue using ffmpeg to stream audio and parse to google cloud speech to text in PHP.

  


  It returns this output.
I have tried delaying some part of the script, that did not solve it.
I have also checked for similar questions. however, they are mostly in python and none of the solutions actually work for this.

  


    built with gcc 8 (GCC)
  cpudetect
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mp3, from 'https://npr-ice.streamguys1.com/live.mp3':
  Metadata:
    icy-br          : 96
    icy-description : NPR Program Stream
    icy-genre       : News and Talk
    icy-name        : NPR Program Stream
    icy-pub         : 0
    StreamTitle     :
  Duration: N/A, start: 0.000000, bitrate: 96 kb/s
    Stream #0:0: Audio: mp3, 32000 Hz, stereo, fltp, 96 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (mp3float) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, s16le, to 'pipe:':
  Metadata:
    icy-br          : 96
    icy-description : NPR Program Stream
    icy-genre       : News and Talk
    icy-name        : NPR Program Stream
    icy-pub         : 0
    StreamTitle     :
    encoder         : Lavf58.29.100
    Stream #0:0: Audio: pcm_s16le, 16000 Hz, mono, s16, 256 kb/s
    Metadata:
      encoder         : Lavc58.54.100 pcm_s16le
**av_interleaved_write_frame(): Broken pipe** 256.0kbits/s speed=1.02x
**Error writing trailer of pipe:: Broken pipe**
size=      54kB time=00:00:01.76 bitrate= 250.8kbits/s speed=0.465x
video:0kB audio:55kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!


  


  this is my PHP code

  


  require_once 'vendor/autoload.php';
    
    $projectId = "xxx-45512";
    putenv('GOOGLE_APPLICATION_CREDENTIALS=' . __DIR__ . '/xxx-45512-be3eb805f1d7.json');
    
    // Database connection
    $pdo = new PDO('mysql:host=localhost;dbname=', '', '');
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    $url = "https://npr-ice.streamguys1.com/live.mp3";
    
    $ffmpegCmd = "ffmpeg -re -i $url -acodec pcm_s16le -ac 1 -ar 16000 -f s16le -";
    
    $fp = popen($ffmpegCmd, "r");
    if (!$fp) {
        die("Failed to open FFmpeg stream.");
    }
    sleep(5);

    try {
        $client = new SpeechClient(['transport' => 'grpc', 'credentials' => json_decode(file_get_contents(getenv('GOOGLE_APPLICATION_CREDENTIALS')), true)]);
    } catch (Exception $e) {
        echo 'Error: ' . $e->getMessage(); 
        exit;
    }
    
    $recognitionConfig = new RecognitionConfig([
        'auto_decoding_config' => new AutoDetectDecodingConfig(),
        'language_codes' => ['en-US'],
        'model' => 'long',
    ]);
    
    $streamingConfig = new StreamingRecognitionConfig([
        'config' => $recognitionConfig,
    ]);
    
    $configRequest = new StreamingRecognizeRequest([
        'recognizer' => "projects/$projectId/locations/global/recognizers/_",
        'streaming_config' => $streamingConfig,
    ]);
    
    
    function streamAudio($fp)
    {
        while (!feof($fp)) {
            yield fread($fp, 4096);
        }
    }
    
    $responses = $client->streamingRecognize([
    'requests' => (function () use ($configRequest, $fp) {
            yield $configRequest; // Send initial config
            foreach (streamAudio($fp) as $audioChunk) {
                yield new StreamingRecognizeRequest(['audio' => $audioChunk]);
            }
        })()]
    );
    
    // $responses = $speechClient->streamingRecognize();
    // $responses->writeAll([$request,]);
    
    foreach ($responses as $response) {
        foreach ($response->getResults() as $result) {
            $transcript = $result->getAlternatives()[0]->getTranscript();
            // echo "Transcript: $transcript\n";
    
            // Insert into the database
            $stmt = $pdo->prepare("INSERT INTO transcriptions (transcript) VALUES (:transcript)");
            $stmt->execute(['transcript' => $transcript]);
        }
    }
    
    
    pclose($fp);
    $client->close();


  


  I'm not sure what the issue is at this time.

  


  UPDATE

  


  I've done some more debugging and i have gotten the error to clear and to stream actually starts.
However, I expect the audio to transcribe and update my database but instead I get this error when i close the stream

  


  

  


  this is my updated code

  


      $handle = popen($ffmpegCommand, "r");

    try {
        $client = new SpeechClient(['transport' => 'grpc', 'credentials' => json_decode(file_get_contents(getenv('GOOGLE_APPLICATION_CREDENTIALS')), true)]);
    } catch (Exception $e) {
        echo 'Error: ' . $e->getMessage(); 
        exit;
    }
    
    try {
    $recognitionConfig = (new RecognitionConfig())
        ->setAutoDecodingConfig(new AutoDetectDecodingConfig())
        ->setLanguageCodes(['en-US'], ['en-UK'])
        ->setModel('long');
    } catch (Exception $e) {
        echo 'Error: ' . $e->getMessage(); 
        exit;
    }
    
    try {
        $streamConfig = (new StreamingRecognitionConfig())
        ->setConfig($recognitionConfig);
    } catch (Exception $e) {
        echo 'Error: ' . $e->getMessage();
        exit;
    }
    try {
        $configRequest = (new StreamingRecognizeRequest())
        ->setRecognizer("projects/$projectId/locations/global/recognizers/_")
        ->setStreamingConfig($streamConfig);
    } catch (Exception $e) {
        echo 'Error: ' . $e->getMessage(); 
        exit;
    }
    
    $stream = $client->streamingRecognize();
    $stream->write($configRequest);
    
    mysqli_query($conn, "INSERT INTO transcriptions (transcript) VALUES ('bef')");
    
    while (!feof($handle)) {
        $chunk = fread($handle, 25600);
        // printf('chunk: ' . $chunk);
        if ($chunk !== false) {
            try {
                $request = (new StreamingRecognizeRequest())
                        ->setAudio($chunk);
                    $stream->write($request);
            } catch (Exception $e) {
                printf('Errorc: ' . $e->getMessage());
            }
        }
    }
    
    
    $insr = json_encode($stream);
    mysqli_query($conn, "INSERT INTO transcriptions (transcript) VALUES ('$insr')");
    
    foreach ($stream->read() as $response) {
        mysqli_query($conn, "INSERT INTO transcriptions (transcript) VALUES ('loop1')");
        foreach ($response->getResults() as $result) {
            mysqli_query($conn, "INSERT INTO transcriptions (transcript) VALUES ('loop2')");
            foreach ($result->getAlternatives() as $alternative) {
                $trans = $alternative->getTranscript();
                mysqli_query($conn, "INSERT INTO transcriptions (transcript) VALUES ('$trans')");
            }
        }
    }
    
    pclose($handle);
    $stream->close();
    $client->close();```