没有直接可用的列表。您必须运行
对于输入格式，ffmpeg -demuxers
对于输出格式，ffmpeg -muxers
然后对每个条目运行
对于输入格式，ffmpeg -h demuxer=entry
对于输出格式，ffmpeg -h muxer=entry
每种格式的读数会显示如下内容，

Muxer matroska [Matroska]:
    Common extensions: mkv.
    Mime type: video/x-matroska.
    Default video codec: h264.
...

或

Demuxer avi [AVI (Audio Video Interleaved)]:
    Common extensions: avi.
...

然后您可以从Common extensions条目中收集所有扩展名。

根据Gyan的答案，我使用了一个python脚本来获取ffmpeg的所有可能扩展，用于其复用器和解复用器：

ffmpeg = 'c:/ffmpeg/bin/ffmpeg.exe'

LINE_PATTERN = r' +\S+ +(\S+)'
EXT_PATTERN = r'Common extensions: (.+)\.'

# Get demuxers
output = subprocess.getoutput([ffmpeg, '-hide_banner', '-demuxers'])
lines = output.split('\n')[4:]

demuxers = {}
for line in lines:
  demuxer = re.findall(LINE_PATTERN, line)[0]
  
  info = subprocess.getoutput([ffmpeg, '-hide_banner', '-h', f'demuxer={demuxer}'])
  exts = re.findall(EXT_PATTERN, info)
  if exts:
    demuxers[demuxer] = exts[0].split(',')

# Get muxers
output = subprocess.getoutput([ffmpeg, '-hide_banner', '-muxers'])
lines = output.split('\n')[4:]

muxers = {}
for line in lines:
  muxer = re.findall(LINE_PATTERN, line)[0]

  info = subprocess.getoutput([ffmpeg, '-hide_banner', '-h', f'muxer={muxer}'])
  exts = re.findall(EXT_PATTERN, info)
  if exts:
    muxers[muxer] = exts[0].split(',')

# Write extensions
f = open('ffmpeg_extensions.txt', 'w')

exts = set()
for ext in demuxers.values():
  [exts.add(x.strip()) for x in ext]
for ext in muxers.values():
  [exts.add(x.strip()) for x in ext]
for ext in sorted(exts):
  f.write(ext + '\n')

f.close()