使用FFmpeg转换视频适配支持MPEG-4/DivX的DVD-225播放器的技术求助

Hey Neil, let's break down why your converted videos only play audio and fix your ffmpeg script to match the DVD-225's strict playback requirements. Comparing the working vs. non-working file metadata, there are three critical mismatches causing the problem:

1. Resolution & Pixel Aspect Ratio (PAR) Mismatch #

Your working video uses 640x290 resolution with square pixels (SAR 1:1), but your converted output has 1280x720 with a non-square SAR (3:4). Most budget DVD players (even "newer" USB-enabled models) have hard resolution limits and only support square pixels—non-square ratios or overly high resolutions will break video decoding entirely.

2. Unlocked MPEG-4 Profile #

Even though you're using mpeg4 encoding, ffmpeg defaults to higher profiles like Advanced Simple Profile that your DVD-225 doesn't support. The working file explicitly uses MPEG-4 Simple Profile, which you need to force in your script to align with the player's capabilities.

3. Timebase (tbc) Inconsistency #

The working video uses a timebase of 23.98 tbc, but your converted file uses 24k tbc. This mismatch throws off the player's frame synchronization, leading to no video output even if the audio stream works.

Corrected ffmpeg Script #

Here's a revised script that locks in all the parameters your DVD-225 expects, ensuring full playback compatibility:

for i in *.avi *.mkv *.mp4; do
  ffmpeg -i "$i" \
    -c:v mpeg4 -vtag divx \
    -profile:v simple -level:v 3.0 \  # Force Simple Profile (critical for compatibility)
    -s 640x290 -aspect 64:29 \       # Match working file's resolution and display ratio
    -r 23.98 \                       # Lock to 23.98fps to match the working file
    -c:a libmp3lame -qscale:a 4 \
    -ar 48000 -ac 2 \                # Explicitly set audio specs: 48kHz stereo
    -f avi -aviopts format=odml \     # Ensure support for large AVI files
    "_${i%.*}.avi"
done

Optional Flexible Adjustments #

• If you don't want to hardcode 640x290, use this scale filter to automatically resize to a player-friendly square-pixel resolution (adjust max values if needed):

  -vf "scale='min(720,iw)':'min(480,ih)',setsar=1:1"
  

• Test with a single file first to validate before batch processing:

  ffmpeg -i test.mkv -c:v mpeg4 -vtag divx -profile:v simple -level:v 3.0 -s 640x290 -r 23.98 -c:a libmp3lame -qscale:a 4 -ar 48000 -ac 2 test_fixed.avi
  

• If you still have issues, try lowering the MPEG-4 level to 2.0 (some older players only support this baseline level) by changing -level:v 2.0.

Key Context #

The DVD-225's "MPEG-4/DivX" support is likely limited to DivX 3/4-era Simple Profile specs, not modern MPEG-4 variants. By locking all parameters to match your working file exactly, you'll eliminate compatibility gaps with its strict USB playback engine.

内容的提问来源于stack exchange，提问作者Neil Telford