diff --git a/docs/tech_docs/linux/video_capture.md b/docs/tech_docs/linux/video_capture.md index 4dfd838..4db29d0 100644 --- a/docs/tech_docs/linux/video_capture.md +++ b/docs/tech_docs/linux/video_capture.md @@ -1,3 +1,80 @@ +Absolutely, let's refine this workflow and outline a step-by-step approach, including examples of how you might use these tools together to achieve a complete video editing workflow on Linux. This will give you a solid starting point and an idea of how to expand or modify the workflow based on your specific requirements. + +### Step 1: Preparing Your Video and Audio Sources + +Before starting, ensure all video clips and audio tracks you intend to use are organized and accessible. Decide on the final video's structure, including which clips to merge, any sections to trim, and where to overlay audio. + +### Step 2: Basic Video Processing with FFmpeg + +**Trimming and Merging Clips:** + +1. **Trim Video Clips**: If you need to trim your video clips, use FFmpeg's `-ss` (start time) and `-to` (end time) options. + ```bash + ffmpeg -i input.mp4 -ss 00:00:10 -to 00:01:00 -c copy trimmed_output.mp4 + ``` + +2. **Merge Video Clips**: To merge multiple clips without re-encoding, first create a text file (`file_list.txt`) listing each file you want to merge, formatted as `file 'path/to/file.mp4'`. Then, use the concat demuxer: + ```bash + ffmpeg -f concat -safe 0 -i file_list.txt -c copy merged_output.mp4 + ``` + +**Adjusting Video Quality or Format:** + +- **Change Codec or Quality**: Transcode your video to a different codec or adjust quality settings. This is useful for standardizing formats or preparing for web upload: + ```bash + ffmpeg -i merged_output.mp4 -vcodec libx264 -crf 23 output_transcoded.mp4 + ``` + +### Step 3: Advanced Audio Editing with SoX + +If your project involves custom audio tracks or you need to clean up existing audio, SoX can be a powerful tool. + +1. **Noise Reduction**: To remove background noise from an audio sample, first create a noise profile, then apply noise reduction: + ```bash + sox noise_sample.wav -n noiseprof noise.profile + sox input_audio.wav output_clean.wav noisered noise.profile 0.21 + ``` + +2. **Merge or Overlay Audio**: Combine audio tracks or overlay them onto your video. While SoX can handle complex audio processing, you'll likely use FFmpeg to merge the cleaned or created audio tracks with your video. + +### Step 4: Using Avidemux for Filters and Quick Edits + +While Avidemux is more GUI-oriented, for certain tasks, it might offer a quicker workflow than scripting FFmpeg commands, especially for applying filters or doing quick cuts that don't require precise scripting. + +- **Quick Cuts**: Open Avidemux, load your video, and use the GUI to trim or split your video visually. +- **Applying Filters**: Access Avidemux's filter library to adjust colors, apply deinterlace filters, or resize your video. + +### Step 5: Final Assembly with MKVToolNix + +Once you have your edited video and audio tracks: + +1. **Merging Subtitles or Additional Audio Tracks**: Use `mkvmerge` to include subtitles or the edited audio tracks into your video without re-encoding: + ```bash + mkvmerge -o final_video.mkv video_file.mp4 audio_file.wav subtitles.srt + ``` + +### Step 6: Optimizing Workflow with GNU Parallel + +For batch processing tasks (like transcoding multiple files), GNU Parallel can significantly reduce processing time: + +```bash +ls *.mp4 | parallel ffmpeg -i {} -vcodec libx264 -crf 23 {.}_transcoded.mp4 +``` + +This command transcodes all MP4 files in the current directory to a lower CRF value using libx264, running multiple jobs in parallel depending on your CPU. + +### Getting Started + +- **Installation**: Most distros support easy installation via package managers (e.g., `apt`, `dnf`). +- **Documentation and Tutorials**: Each tool has extensive documentation and community tutorials. Start with basic tasks to familiarize yourself with the command syntax and capabilities. +- **Experimentation**: Experimenting with each tool will help you understand its capabilities and limitations, allowing you to tailor the workflow to your needs. + +### Conclusion + +This refined workflow combines the strengths of several powerful, open-source tools to cover a broad spectrum of video editing tasks, from basic cuts to advanced audio processing and final assembly. By leveraging these tools' command-line interfaces, you can automate repetitive tasks, handle batch processing efficiently, and maintain a high degree of control over your video production process. + +--- + Based on our discussion and the successful execution of the command to capture and scale a specific window on your Debian system, let's create a more general guide. This guide will be adaptable for various scenarios, allowing you to tweak settings as necessary for your specific needs. ### General Guide for Capturing and Scaling Windows with FFmpeg on Linux