Please help ffmpeg

[Bmcaps]

Hello All

I have a friend in an institution. He only has access to a SanDisk sansa clip sport mp3 player, but it has been modded to run firmware for a Ruizu X10 mp3 player.

It can display videos in amv format only, due to the weak processor.

He is converting MP4 videos on an Android phone using ffmpeg, using the following commands:

-c:v amv -c:a adpcm_ima_amv -pix_fmt yuvj420p -vf
"scale=148:128:force_original_aspect_ratio=decreas e,crop=128:in_h:10:0,pad=160:128:32:-1:c
olor=black" -vstrict -1 -r 30 -ac 1 -ar 22050 -block_size 735

However, the video quality is poor, blurry.

We are completely new to this and don't understand the code above.

Can you guys please help tweak the code to deliver better video quality that the weak mp3 processor can still handle?

If possible, please just tell us what to type in the ffmpeg template box, because we are very new.

The command to resize the video is necessary because the firmware on the mp3 player was made for a larger screen.

Maybe 30fps is unnecessary? Not sure

Thank you all!!!


[october262]

Hello All

I have a friend in an institution. He only has access to a SanDisk sansa clip sport mp3 player, but it has been modded to run firmware for a Ruizu X10 mp3 player.

It can display videos in amv format only, due to the weak processor.

He is converting MP4 videos on an Android phone using ffmpeg, using the following commands:

-c:v amv -c:a adpcm_ima_amv -pix_fmt yuvj420p -vf
"scale=148:128:force_original_aspect_ratio=decreas e,crop=128:in_h:10:0,pad=160:128:32:-1:c
olor=black" -vstrict -1 -r 30 -ac 1 -ar 22050 -block_size 735

However, the video quality is poor, blurry.

We are completely new to this and don't understand the code above.

Can you guys please help tweak the code to deliver better video quality that the weak mp3 processor can still handle?

If possible, please just tell us what to type in the ffmpeg template box, because we are very new.

The command to resize the video is necessary because the firmware on the mp3 player was made for a larger screen.

Maybe 30fps is unnecessary? Not sure

Thank you all!!!


try this here - https://vsubhash.wordpress.com/2014/03/02/how-to-convert-any-video-file-to-amv-using-ffmpeg/

[Bmcaps]

Thanks for the reply. The amv conversion script that I wrote in the original post above works fine, only I just want to know what I can modify in the script to improve video quality, if anything.

Can anyone suggest what I can alter in the code above to improve video quality?

We can only use an android phone, no computer.

Thanks again

[davexnet]

The -qscale parameter as mentioned by that article controls the quality. Perhaps you should do some test encodes
to see the effect of different values, etc.

[Bmcaps]

Here is a suggested FFmpeg command that may improve the video quality for your friend's SanDisk Sansa Clip Sport MP3 player:

```
-c:v amv -c:a adpcm_ima_amv -pix_fmt yuv420p -vf "scale=148:128:flags=lanczos,crop=128:in_h:10:0,pa d=160:128:32:-1:color=black" -vstrict -1 -r 15 -b:v 512k -ac 1 -ar 22050 -block_size 735
```

The key changes:

- Use yuv420p pixel format instead of yuvj420p - this is a more efficient format for the device.

- Use the Lanczos scaling algorithm instead of default - helps reduce blurriness.

- Reduce frame rate to 15 fps - the lower frame rate will reduce blur from motion.

- Add a video bitrate limit of 512k - constrains the video quality to what the device can handle.

- Remove the -vstrict -1 option - it is unnecessary.

Let me know if this improved the video quality on the device! I can explain the changes more or tweak further if needed. The goal is to get the best quality within the device's constraints.

Thanks so much.

I tried your script. The video quality looked slightly better.
Also the video changed from widescreen to full screen, erasing the black bars on the top and bottom of the video. This is great because the screen is only one inch. Will this negatively affect videos that are native full screen or other odd aspects ratios?

Finally, is there anything I can change or add to further improve video quality?

Thank you so much

[Bmcaps]

Thanks all for the responses.

I added commands to the end of my original script, such as -q:v, -qmin and max, -crf, and -b:v, then altered the values.

For example, in one test convert, I added -q:v 4 to the very end of my original script.

For some reason, no matter how I change these quality values, the converted videos are the exact same file size and look identical on the mp3 player.

So:

1) do I need to add these commands to a certain place in the script for them to work?

2) does the amv codec force a certain quality level that I can't change?

Thanks again