Python文件中的FFmpeg已存在错误

我正在研究一个使用python（3.6）和Django（2.0）的项目，其中我将视频转换为mp4，如果它在任何其他合成中 .

这是我的代码：

from views.py:

def generate_thumbnail(filename, thumb_name):
    print('func called')
    print(filename)
    video_input_path = os.path.join(filename)
    img_output_path = os.path.join(thumb_name)
    subprocess.call(['ffmpeg', '-i', video_input_path, '-ss', '00:00:00.000', 'vframes', '1', img_output_path])


def convert_to_mp4(video_name, only_name):
    os.popen(
        "ffmpeg -i '{input}' -ac 2 -b:v 2000k -c:a aac -c:v libx264 -b:a 160k -vprofile high -bf 0 -strict experimental -f mp4 '{output}.mp4'".format(
            input=video_name, output=only_name))
    return True


def perform_upload(video, thumbnail):
    print('vdieo name is: {}'.format(video))
    servise = discovery.build('storage', 'v1', credentials=credentials)
    bucket_name = 'test_bucket004'
    print('Uploading the video...')
    media = MediaFileUpload(video, chunksize=4149304, mimetype='video/mp4',
                            resumable=True)
    req = servise.objects().insert(
        bucket=bucket_name,
        name=str(video),
        media_body=media,
        body={"cacheControl": "public,max-age=31536000"},
        predefinedAcl='publicRead'
    )
    resp = None
    while resp is None:
        status, resp = req.next_chunk()
    print(resp)
    video_url = 'http://storage.googleapis.com/' + bucket_name + '/' + str(video)

    print('Uploading your thumbnail...')
    media = MediaFileUpload(thumbnail, chunksize=4149304, mimetype='image/jpeg',
                            resumable=True)
    req = servise.objects().insert(
        bucket=bucket_name,
        name=str(thumbnail),
        media_body=media,
        body={"cacheControl": "public,max-age=31536000"},
        predefinedAcl='publicRead'
    )
    resp = None
    while resp is None:
        status, resp = req.next_chunk()
    print(resp)
    thumb_url = 'https://storage.googleapis.com/' + bucket_name + '/' + str(thumbnail)

    return video_url, thumb_url


class VideoConverter(generics.ListCreateAPIView):
    def get(self, request, *args, **kwargs):
        return HttpResponse('Get request', status=200)

    def post(self, request, *args, **kwargs):
        serializer = VideoConverterSerializer(data=self.request.data)
        validation = serializer.is_valid()
        print(serializer.errors)
        if validation is True:
            url = request.POST.get('video_url')
            filename = url.split('/')
            filename = filename[-1]
            print(filename)
            ext = filename.split('.')
            print(ext[-1])
            only_name = ext[0]
            urllib.request.urlretrieve(url, filename)
            generate_thumbnail(filename, only_name + '_thumbnail.jpg')
            if ext == 'mp4':
                videourl, thumb_url = perform_upload(filename, only_name + '_thumbnail.jpg')
            else:
                conversion = convert_to_mp4(filename, only_name)
                if conversion is True:
                    videourl, thumb_url = perform_upload(only_name + '.mp4', only_name + '_thumbnail.jpg')

            return HttpResponse('Video url is: {}\n \nThumbnail url is: {}'.format(videourl, thumb_url))
        else:
            return HttpResponse('Not a valid request')

但是当我传递一个Mp4格式的视频时，它在IDE控制台中返回一个错误，如下所示：

ffmpeg版本4.0.2版权所有（c）2000-2018 FFmpeg开发人员使用Apple LLVM版本10.0.0（clang-1000.10.43.1）配置： - prefix = / usr / local / Cellar / ffmpeg / 4.0.2 - -enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc = clang --host-cflags = --host-ldflags = --enable-gpl - enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma libavutil 56. 14.100 / 56. 14.100 libavcodec 58. 18.100 / 58. 18.100 libavformat 58. 12.100 / 58 .12.100 libavdevice 58. 3.100 / 58. 3.100 libavfilter 7. 16.100 / 7. 16.100 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 1.100 / 5. 1.100 libswresample 3. 1.100 / 3. 1.100 libpostproc 55. 1.100 / 55. 1.100输入＃0，mov，mp4，m4a，3gp，3g2，mj2，来自'PHP_GCS.mp4'：元数据：major_brand：mp42 minor_version：1 compatible_brands：mp41mp42isom creation_time：2018-08-03T13：08：04.000000Z持续时间：00：01：21.40，开始：0.000000，比特率：1584 kb / s流＃0：0（und）：视频：h264（主）（avc1 / 0x31637661），yuv420p，1918x1078 [SAR 1：1 DAR 137：77]，1581 kb / s，30 fps，30 tbr，600 tbn，1200 tbc（默认）元数据：creation_time：2018 -08-03T13：08：04.000000Z handler_name：核心媒体视频文件'PHP_GCS.mp4'已存在 . 覆盖？ [Y / N]

并在此处停止执行，直到我按下回车键 . 我'm really confused why this is happining because when the video is already mp4 i' m不使用 ffmpeg 但仅用于缩略图生成 .

这可能有什么不对？

提前致谢！