til: ffmpeg: add 'Merge audio and video files'

Merging audio and video files can be done efficiently using the
'ffmpeg' tool.

This TIL provides a clear and concise explanation for how to use the
'ffmpeg' tool to merge a video and an audio file into a single output
file. It also contains an example for illustration purposes.

Signed-off-by: Stefan Kühnel <[email protected]>

Author: stefankuehnel

content/ffmpeg/merge_audio_and_video_files.md

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+title = "Merge audio and video files"
+date = 2024-11-23
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+
+Merging audio and video files can be done efficiently using the `ffmpeg` tool. This process is often used when video and audio streams are stored in separate files and need to be combined into a single file.
+
+The following `ffmpeg` command demonstrates how to merge a video file with an audio file into a single output file:
+
+```bash
+$ ffmpeg -i input_video.mp4 -i input_audio.mp3 -c:v copy -c:a aac -map 0:v:0 -map 1:a:0 output.mp4
+```
+
+The command contains multiple options:
+
+- `-i input_video.mp4`: Specifies the input video file.
+- `-i input_audio.mp3`: Specifies the input audio file.
+- `-c:v copy`: Copies the video codec without re-encoding.
+- `-c:a aac`: Encodes the audio to AAC format.
+- `-map 0:v:0`: Maps the video stream from the first input file.
+- `-map 1:a:0`: Maps the audio stream from the second input file.
+- `output.mp4`: Name of the output file.
+
+## Bibliography
+
+Bellard, F. (2000). _FFmpeg Documentation_. FFmpeg Project. [https://ffmpeg.org/documentation.html](https://ffmpeg.org/documentation.html)