CRAIG's questions

我有一个在 Quicktime 中播放良好的视频。当通过 FFMPEG 运行时，ffmpeg 正在垂直翻转它。但是，我的命令不包括翻转命令：

/usr/local/bin/ffmpeg     -safe 0 -f concat -i  concat.txt    -i videogettingflipped.MOV         
-filter_complex "[1]scale=1280:-2,pad=1280:1280:0:280[1v];[1v][0]overlay=0:0 "  
-aspect 1:1  -c:v libx264 -profile:v baseline -pix_fmt yuv420p -level 3.1  
-map 1:a  -c:a aac -b:a 128k      -r 30    -y  finalvideo.mp4

这是来自 ffprobe 的 JSON，旋转表示 0，我认为它没有旋转。该数据中是否还有其他内容告诉 FFMPEG 翻转该视频？

{
    "streams": [
        {
            "index": 0,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "profile": "LC",
            "codec_type": "audio",
            "codec_time_base": "1/44100",
            "codec_tag_string": "mp4a",
            "codec_tag": "0x6134706d",
            "sample_fmt": "fltp",
            "sample_rate": "44100",
            "channels": 2,
            "channel_layout": "stereo",
            "bits_per_sample": 0,
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/44100",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10168505,
            "duration": "230.578345",
            "bit_rate": "200216",
            "max_bit_rate": "192000",
            "nb_frames": "9933",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0
            },
            "tags": {
                "rotate": "0",
                "creation_time": "2020-03-25T02:06:14.000000Z",
                "language": "und",
                "handler_name": "Core Media Audio"
            }
        },
        {
            "index": 1,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
            "profile": "High",
            "codec_type": "video",
            "codec_time_base": "138347/8300400",
            "codec_tag_string": "avc1",
            "codec_tag": "0x31637661",
            "width": 1280,
            "height": 720,
            "coded_width": 1280,
            "coded_height": 720,
            "has_b_frames": 1,
            "pix_fmt": "yuv420p",
            "level": 31,
            "color_range": "tv",
            "color_space": "bt709",
            "color_transfer": "bt709",
            "color_primaries": "bt709",
            "chroma_location": "left",
            "refs": 1,
            "is_avc": "true",
            "nal_length_size": "4",
            "r_frame_rate": "30/1",
            "avg_frame_rate": "4150200/138347",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 138347,
            "duration": "230.578333",
            "bit_rate": "2518518",
            "bits_per_raw_sample": "8",
            "nb_frames": "6917",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0
            },
            "tags": {
                "rotate": "0",
                "creation_time": "2020-03-25T02:06:14.000000Z",
                "language": "und",
                "handler_name": "Core Media Video",
                "encoder": "H.264"
            },
            "side_data_list": [
                {
                    "side_data_type": "Display Matrix",
                    "displaymatrix": "\n00000000:        65536           0           0\n00000001:            0      -65536           0\n00000002:            0    47185920  1073741824\n",
                    "rotation": 0
                }
            ]
        }
    ],
    "format": {
        "filename": "video.MOV",
        "nb_streams": 2,
        "nb_programs": 0,
        "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
        "format_long_name": "QuickTime / MOV",
        "start_time": "0.000000",
        "duration": "230.578333",
        "size": "78501353",
        "bit_rate": "2723633",
        "probe_score": 100,
        "tags": {
            "major_brand": "qt  ",
            "minor_version": "0",
            "compatible_brands": "qt  ",
            "creation_time": "2020-03-25T02:06:14.000000Z",
            "com.apple.quicktime.make": "Apple",
            "com.apple.quicktime.model": "iPhone 11",
            "com.apple.quicktime.software": "13.3.1",
            "com.apple.quicktime.creationdate": "2020-03-17T15:06:47-0400"
        }
    }
}

我正在使用此命令将覆盖的图像从黑色背景滑到右侧。

ffmpeg -f lavfi -i color=color=black:d=15:size=1920x1080,format=rgba[background]; movie=pinkimage.png[overlay]; [background][overlay]overlay='min(n*5-0\,1920):(H-h)/2'" output.mp4

我理解是“n”参数的操作会影响转换的速度，但我不明白为什么或如何。我希望它的视频长度为 15 秒，此处设置为：“d = 15”。

那么，我怎样才能使叠加动画也花费 15 秒呢？

我正在使用以下代码获取许多不同持续时间的 PNG，并将它们覆盖在另一个视频上。

ffmpeg  -safe -0 -f concat -i  overlap-png.txt 
-i mainvideo.MOV -filter_complex "[1]scale=1920:-1[1v];[0:v]fps=30[0v];[1v][0v]overlay=0:0"  
-c:v libx264 -profile:v baseline -pix_fmt yuv420p 
-level 3.1 -y  finishedvideo.mp4

然而，我发现了一件非常奇怪的事情。.txt 文件中提到的 PNG 文件基本上都是透明的，除了底部的一个大约 300 像素左右的条。如果该条为深灰色，则一切正常。

如果该条为红色，则许多图像被丢弃或帧可能被丢弃。

此外，我注意到脚本的运行方式不同，具体取决于条形是红色还是深灰色。如果它是红色的，则有更多的逐行处理，如果它是深灰色，则似乎在一行处理中发生了相同的编码。

我正在使用 ffmpeg 转换/缩放视频，并将音频流导出到单个音频文件。

/usr/local/bin/ffmpeg  -i video.mov -vf  scale="480:480"   -c:v libx264 -profile:v baseline -preset ultrafast -crf 22 -c:a aac  -pix_fmt yuv420p -y video-output.mp4  -y audio-output.mp3

但是，如果视频缺少音频文件，它就会中断。

如果没有音频，有没有办法忽略音频导出？