Recherche avancée

Sur d’autres sites (10948)

• Setting bitrate of video in ffmpeg using C++

  9 août 2017, par ngân phạm

  Firstly, I know this is an old question. I use FFmpeg to record video from a RTSP stream (the codec is H.264). It works. But I face a problem with the bitrate value. First, I set bitrate like below, but not work :

  AVCodecContext *m_c;
  
  m_c->bit_rate = bitrate_value; 

  Following this question I can set bitrate manually with this command

  av_opt_set(m_c->priv_data, "crf", "39", AV_OPT_SEARCH_CHILDREN);

  But I have to test serveral times to choose value ’39’, which create acceptable video quality. It’s hard to do again if I use another camera setting (image width, height,...). Is there a way to set bitrate more easily, and adaptively ?

• Stream openCv video frames to an rtmp server using ffmpeg

  1er décembre 2022, par seriously

  I am using openCv and face-recognition api to detect a face using a webcam then compare it with a previously taken image to check and see if the people on both images are the same and the openCv and face-recognition part of the code works properly now what I am trying to achieve is to stream the openCv processed video frames to an rtmp server so for this I am trying to use ffmpeg and running the command using subprocess but when I run the code I get error FileNotFoundError: [WinError 2] The system cannot find the file specified. Which file is it refering to ? All I did was pipe the frames I get from openCv to ffmpeg. How can I fix it and properly stream my openCv frames to an rtmp server using ffmpeg. Thanks in advance.

  


  Traceback (most recent call last):&#xA;  File "C:\Users\blah\blah\test.py", line 52, in <module>&#xA;    p = subprocess.Popen(command, stdin=subprocess.PIPE, shell=False)&#xA;  File "C:\Python310\lib\subprocess.py", line 969, in __init__&#xA;    self._execute_child(args, executable, preexec_fn, close_fds,&#xA;  File "C:\Python310\lib\subprocess.py", line 1438, in _execute_child&#xA;    hp, ht, pid, tid = _winapi.CreateProcess(executable, args,&#xA;FileNotFoundError: [WinError 2] The system cannot find the file specified&#xA;</module>

  


  import cv2
import numpy as np
import face_recognition
import ffmpeg
import os
import subprocess

path = '../imgs'
imgs = []
classNames = []
myList = os.listdir(path)

for cls in myList:
    curruntImg = cv2.imread(f'{path}/{cls}')
    imgs.append(curruntImg)
    classNames.append(os.path.splitext(cls)[0])

def findEncodings(imgs):
    encodeList = []
    for img in imgs:
        img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        encode = face_recognition.face_encodings(img)[0]
        encodeList.append(encode)
    return encodeList

encodeListKnown = findEncodings(imgs)
print('Encoding Complete')

cap = cv2.VideoCapture(0)

rtmp_url = "rtmp://127.0.0.1:1935/stream/webcam"

fps = int(cap.get(cv2.CAP_PROP_FPS))
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

# command and params for ffmpeg
command = ['ffmpeg',
           '-y',
           '-f', 'rawvideo',
           '-vcodec', 'rawvideo',
           '-pix_fmt', 'bgr24',
           '-s', "{}x{}".format(width, height),
           '-r', str(fps),
           '-i', '-',
           '-c:v', 'libx264',
           '-pix_fmt', 'yuv420p',
           '-preset', 'ultrafast',
           '-f', 'flv',
           rtmp_url]

p = subprocess.Popen(command, stdin=subprocess.PIPE)


while cap.isOpened():
    ret, frame, success, img = cap.read()
    if not ret:
        print("frame read failed")
        break
    imgSmall = cv2.resize(img, (0,0), None, 0.25, 0.25)
    imgSmall = cv2.cvtColor(imgSmall, cv2.COLOR_BGR2RGB)

    currentFrameFaces = face_recognition.face_locations(imgSmall)
    currentFrameEncodings = face_recognition.face_encodings(imgSmall, currentFrameFaces)

    for encodeFace, faceLocation in zip(currentFrameEncodings, currentFrameFaces):
        matches = face_recognition.compare_faces(encodeListKnown, encodeFace)
        faceDistance = face_recognition.face_distance(encodeListKnown, encodeFace)
        matchIndex = np.argmin(faceDistance)

        if matches[matchIndex]:
            name = classNames[matchIndex].upper()
            y1, x2, y2, x1 = faceLocation
            y1, x2, y2, x1 = y1 * 4, x2 * 4, y2 * 4, x1 * 4 
            cv2.rectangle(img, (x1, y1), (x2, y2), (0, 255, 0), 2)
            cv2.rectangle(img, (x1, y2 - 35), (x2, y2), (0, 255, 0), cv2.FILLED)
            cv2.putText(img, name, (x1 + 6, y2 - 6), cv2.FONT_HERSHEY_DUPLEX, 1, (255, 255, 255), 2)

    # write to pipe
    p.stdin.write(frame.tobytes())


  


• mp4 muxing problems on dm365 board

  25 mai 2013, par Ulterior

  I happen to be stuck with strange TI codec issues while encoding video. To cut story short - the encoded data which is generated by TI mpeg4 codecs are not 'understood' by nothing else, but VLC and media classic player.

  After really long googling and several seasons I face to you stackoverlowers to help me understand what is wrong in the encoded frame headers, because I really fail to find any answers.

  AviDemux 2.6.1 opens and remux-es video data without problems. So there is hope to understand whats is wrong with mp4 generated data...

  I would really appreciate any help from mp4 gurus out there...

  the link to the problem file