av ops using ffmpeg

Author: Bhupesh-V

.vitepress/sidebar.js

@@ -287,6 +287,10 @@ export const sidebar = [
   {
     "text": "Ffmpeg",
     "items": [
+      {
+        "text": "Audio/Video Ops",
+        "link": "/ffmpeg/av-ops"
+      },
       {
         "text": "Converting videos to High quality GIFs",
         "link": "/ffmpeg/converting-videos-to-high-quality-gif"

README.md

@@ -43,7 +43,7 @@
 </tr>
 <tr>
 <td><a href="#distributed-computing">Distributed Computing</a><sup>[3]</sup></td>
-<td><a href="#ffmpeg">Ffmpeg</a><sup>[3]</sup></td>
+<td><a href="#ffmpeg">Ffmpeg</a><sup>[4]</sup></td>
 <td><a href="#flutter">Flutter</a><sup>[3]</sup></td>
 </tr>
 <tr>
@@ -246,6 +246,7 @@
 ### Ffmpeg
 
 <ul>
+<li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/ffmpeg/av-ops.md">Audio/Video Ops</a></li>
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/ffmpeg/converting-videos-to-high-quality-gif.md">Converting videos to High quality GIFs</a></li>
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/ffmpeg/generate-video-thumbnail-using-ffmpeg.md">Generate Video thumbnail using ffmpeg</a></li>
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/ffmpeg/record-your-desktop-using-ffmpeg-on-linux.md">Record your Desktop using ffmpeg</a></li>

count.json

@@ -1,3 +1,3 @@
 {
- "count": 184
+ "count": 185
 }

ffmpeg/av-ops.md

@@ -0,0 +1,53 @@
+# Audio/Video Ops
+
+## Reducing Background Noise
+
+```sh
+ffmpeg -i input.mp4 -af "afftdn=nr=12:nf=-25" -c:v copy output.mp4 
+ffmpeg -i input.mp4 -af "anlmdn=s=0.001" -c:v copy output.mp4
+```
+
+- `afftdn`: Activates the FFT denoise filter.
+- `nr=12`: Noise reduction strength in dB (default is 12). Increase this value for stronger noise removal, but values too high may distort human speech.
+- `nf=-25`: Noise floor in dB (default is -25). Adjusts the threshold below which audio is treated as noise.
+- `-c:v copy`: Copies the video stream directly without re-encoding to save processing time and preserve original video quality.
+
+
+## Video to Audio
+
+```
+ffmpeg -i input.mp4 -b:a 192k output.mp3
+```
+
+- `-b:a` is bitrate, use 192k or 320k.
+
+## Waveform Videos
+
+This creates a white colored wave form on a black background
+```
+ffmpeg -i audio.mp3 -filter_complex "[0:a]showwaves=s=1280x720:mode=line:colors=white" -c:v libx264 -preset fast -crf 23 -c:a copy output.mp4
+```
+
+ffmpeg -y -i final.mp3 -loop 1 -i bg.jpg -filter_complex "[0:a]showwaves=s=1920x300:colors=0x00A8E8:mode=cline,format=rgba[v];[1:v][v]overlay=0:780[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a aac -shortest -pix_fmt yuv420p final_podcast.mp4
+
+ffmpeg -y -i final.mp3 -loop 1 -i bg.jpeg -filter_complex "[0:a]showwaves=s=1080x100:colors=0x00A8E8:mode=cline,format=rgba[wave];[1:v][wave]overlay=0:260:shortest=1[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a aac -pix_fmt yuv420p final_podcast.mp4
+
+ffmpeg -y -i final.mp3 -loop 1 -i bg.jpeg -filter_complex "[0:a]showwaves=s=1080x200:colors=0xFFD700:mode=cline,format=rgba[wave];[1:v][wave]overlay=0:160:shortest=1[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a aac -pix_fmt yuv420p final_podcast.mp4
+
+<!-- ffmpeg -i input -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a -c:v libx264 -c:a copy output.mkv -->
+
+<!-- ffmpeg -i final.mp3 -loop 1 -i bg.jpeg -filter_complex "[0:a]showwaves=s=1080x200:colors=0xFFD700:mode=line,format=yuv420p[v];[1:v][wave]overlay=0:160:shortest=1[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a aac -pix_fmt yuv420p final_podcast.mp4 -->
+
+### Circular Waveform
+
+```
+ffmpeg -i ../final.mp3 -loop 1 -i ../bg.jpeg -filter_complex "[0:a]aformat=channel_layouts=mono,showwaves=s=400x400:mode=line:colors=0xff1646:draw=full,geq='p(mod(W/PI*(PI+atan2(H/2-Y,X-W/2)),W), H-2*hypot(H/2-Y,X-W/2))':a='alpha(mod(W/PI*(PI+atan2(H/2-Y,X-W/2)),W), H-2*hypot(H/2-Y,X-W/2))'" -c:v libx264 -pix_fmt yuv420p -c:a aac circular.mp4 -y
+```
+
+[source](https://www.reddit.com/r/ffmpeg/comments/1fwvjb2/comment/lqlx4hd/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)
+
+Variations
+
+```
+ffmpeg -i ../final.mp3 -loop 1 -i ../bg.jpeg -filter_complex "[0:a]aformat=channel_layouts=mono,showwaves=s=650x650:mode=line:colors=0xFFD700:draw=full,geq='p(mod(W/PI*(PI+atan2(H/2-Y,X-W/2)),W), H-2*hypot(H/2-Y,X-W/2))':a='alpha(mod(W/PI*(PI+atan2(H/2-Y,X-W/2)),W), H-2*hypot(H/2-Y,X-W/2))'[wave]; [1:v][wave]overlay=(W-w)/2:(H-h)/2" -c:v libx264 -pix_fmt yuv420p -c:a aac -shortest -t 10 circular.mp4 -y
+```

index.md

@@ -30,7 +30,7 @@
 </tr>
 <tr>
 <td><a href="#distributed-computing">Distributed Computing</a><sup>[3]</sup></td>
-<td><a href="#ffmpeg">Ffmpeg</a><sup>[3]</sup></td>
+<td><a href="#ffmpeg">Ffmpeg</a><sup>[4]</sup></td>
 <td><a href="#flutter">Flutter</a><sup>[3]</sup></td>
 </tr>
 <tr>
@@ -72,6 +72,9 @@
 <table align="center">
 <tbody>
 <tr>
+<td><a href="https://til.bhupesh.me/arts/sketching">Sketching</a></td>
+</tr>
+<tr>
 <td><a href="https://til.bhupesh.me/databases/acid">ACID</a></td>
 </tr>
 <tr>
@@ -98,9 +101,6 @@
 <tr>
 <td><a href="https://til.bhupesh.me/databases/postgres-backup-restore">Taking & Restoring Postgres Backups</a></td>
 </tr>
-<tr>
-<td><a href="https://til.bhupesh.me/devops/running-nomad-cluster">How to run a Local Nomad Cluster</a></td>
-</tr>
 </tbody>
 </table>
 
@@ -271,6 +271,7 @@
 ### Ffmpeg
 
 <ul>
+<li><a href="/ffmpeg/av-ops">Audio/Video Ops</a></li>
 <li><a href="/ffmpeg/converting-videos-to-high-quality-gif">Converting videos to High quality GIFs</a></li>
 <li><a href="/ffmpeg/generate-video-thumbnail-using-ffmpeg">Generate Video thumbnail using ffmpeg</a></li>
 <li><a href="/ffmpeg/record-your-desktop-using-ffmpeg-on-linux">Record your Desktop using ffmpeg</a></li>

recent_tils.json

@@ -1,4 +1,8 @@
 [
+ {
+  "title": "Sketching",
+  "url": "https://til.bhupesh.me/arts/sketching"
+ },
  {
   "title": "ACID",
   "url": "https://til.bhupesh.me/databases/acid"
@@ -34,9 +38,5 @@
  {
   "title": "Taking & Restoring Postgres Backups",
   "url": "https://til.bhupesh.me/databases/postgres-backup-restore"
- },
- {
-  "title": "How to run a Local Nomad Cluster",
-  "url": "https://til.bhupesh.me/devops/running-nomad-cluster"
  }
 ]