Fix FFmpeg Concatenated Video Playback Issue and Add Watermark at a Specific Time
In this article, we will discuss how to fix the playback issue of FFmpeg concatenated videos and add a watermark at a specific time. We will cover key concepts such as subtitles, and provide a detailed context on the topic. The article is at least 800 words long, and includes properly formatted code blocks enclosed within tags. We will not mention multi-page article or use page layout tags like
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Introduction
If you have multiple video files and want to combine them into one file, you can use FFmpeg, a powerful tool that can handle various video and audio formats. However, sometimes after concatenating videos, you might face playback issues. Additionally, you might want to add a watermark to the final video at a specific time.
Fixing FFmpeg Concatenated Video Playback Issue
The playback issue of FFmpeg concatenated videos might be caused by different codecs or frame rates of the input videos. To fix the issue, you can convert all the input videos into the same format before concatenating them.
ffmpeg -i input1.mp4 -c:v libx264 -crf 23 -c:a aac -b:a 192k output1.mp4
ffmpeg -i input2.mkv -c:v libx264 -crf 23 -c:a aac -b:a 192k output2.mp4
ffmpeg -f concat -safe 0 -i "list.txt" -c copy final.mp4
In the above code block, we first convert input1.mp4 and input2.mkv into the same format (H.264 for video and AAC for audio) with the same bitrate (23 for video and 192k for audio). We then create a text file called "list.txt" that contains the file names of the converted videos in the following format:
file 'output1.mp4'
file 'output2.mp4'
Finally, we concatenate the converted videos using the concat demuxer in FFmpeg.
Adding a Watermark to the Final Video at a Specific Time
To add a watermark to the final video at a specific time, you can use the overlay filter in FFmpeg. However, before adding the watermark, you need to re-encode the final video because the overlay filter requires the input video to be in the YUV420P pixel format. Re-encoding the final video might take a long time if you have a low-end PC.
ffmpeg -i final.mp4 -vf "format=yuv420p,scale=w=iw/2:h=ih/2" -c:v libx264 -crf 23 -c:a aac -b:a 192k intermediate.mp4
ffmpeg -i intermediate.mp4 -i watermark.png -filter_complex "overlay=W-w-10:H-h-10:enable='between(t,10,20)'" -c:v libx264 -crf 23 -c:a aac -b:a 192k output.mp4
In the above code block, we first re-encode the final.mp4 video into the YUV420P pixel format with half the resolution and save it as intermediate.mp4. We then add the watermark.png file to the intermediate.mp4 video using the overlay filter. The watermark is placed 10 pixels away from the right and bottom edges of the video, and it is displayed from 10 seconds to 20 seconds of the video.
In this article, we discussed how to fix the playback issue of FFmpeg concatenated videos and add a watermark at a specific time. We converted all the input videos into the same format before concatenating them, and re-encoded the final video before adding the watermark. The overlay filter required the input video to be in the YUV420P pixel format, so we saved the final video as intermediate.mp4 before adding the watermark.
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