如需查看全部内容执行
ffmpeg -h full
如需观看特定topic的下的分支，比如想看ffmpeg demux的hls 帮助手册
执行如下
ffmpeg -h demuxer=hls
结果如下：
Demuxer hls [Apple HTTP Live Streaming]:
hls demuxer AVOptions:
-live_start_index .D....... segment index to start live streams at (negative values are from the end) (from INT_MIN to INT_MAX) (default -3)
-allowed_extensions .D....... List of file extensions that hls is allowed to access (default "3gp,aac,avi,flac,mkv,m3u8,m4a,m4s,m4v,mpg,mov,mp2,mp3,mp4,mpeg,mpegts,ogg,ogv,oga,ts,vob,wav")
-max_reload .D....... Maximum number of times a insufficient list is attempted to be reloaded (from 0 to INT_MAX) (default 1000)
-http_persistent .D....... Use persistent HTTP connections (default true)
-http_multiple .D....... Use multiple HTTP connections for fetching segments (default auto)
比如我想看下 muxer 的 hls
执行
ffmpeg -h muxer=hls
结果如下：
Common extensions: m3u8.
Default video codec: h264.
Default audio codec: aac.
Default subtitle codec: webvtt.
hls muxer AVOptions:
-start_number E........ set first number in the sequence (from 0 to I64_MAX) (default 0)
-hls_time E........ set segment length in seconds (from 0 to FLT_MAX) (default 2)
-hls_init_time E........ set segment length in seconds at init list (from 0 to FLT_MAX) (default 0)
-hls_list_size E........ set maximum number of playlist entries (from 0 to INT_MAX) (default 5)
-hls_delete_threshold E........ set number of unreferenced segments to keep before deleting (from 1 to INT_MAX) (default 1)
-hls_ts_options E........ set hls mpegts list of options for the container format used for hls
-hls_vtt_options E........ set hls vtt list of options for the container format used for hls
-hls_wrap E........ set number after which the index wraps (will be deprecated) (from 0 to INT_MAX) (default 0)
-hls_allow_cache E........ explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments (from INT_MIN to INT_MAX) (default -1)
-hls_base_url E........ url to prepend to each playlist entry
-hls_segment_filename E........ filename template for segment files
-hls_segment_size E........ maximum size per segment file, (in bytes) (from 0 to INT_MAX) (default 0)
-hls_key_info_file E........ file with key URI and key file path
-hls_enc E........ enable AES128 encryption support (default false)
-hls_enc_key E........ hex-coded 16 byte key to encrypt the segments
-hls_enc_key_url E........ url to access the key to decrypt the segments
-hls_enc_iv E........ hex-coded 16 byte initialization vector
-hls_subtitle_path E........ set path of hls subtitles
-hls_segment_type E........ set hls segment files type (from 0 to 1) (default mpegts)
mpegts E........ make segment file to mpegts files in m3u8
fmp4 E........ make segment file to fragment mp4 files in m3u8
-hls_fmp4_init_filename E........ set fragment mp4 file init filename (default "init.mp4")
-hls_flags E........ set flags affecting HLS playlist and media file generation (default 0)
single_file E........ generate a single media file indexed with byte ranges
temp_file E........ write segment to temporary file and rename when complete
delete_segments E........ delete segment files that are no longer part of the playlist
round_durations E........ round durations in m3u8 to whole numbers
discont_start E........ start the playlist with a discontinuity tag
omit_endlist E........ Do not append an endlist when ending stream
split_by_time E........ split the hls segment by time which user set by hls_time
append_list E........ append the new segments into old hls segment list
program_date_time E........ add EXT-X-PROGRAM-DATE-TIME
second_level_segment_index E........ include segment index in segment filenames when use_localtime
second_level_segment_duration E........ include segment duration in segment filenames when use_localtime
second_level_segment_size E........ include segment size in segment filenames when use_localtime
periodic_rekey E........ reload keyinfo file periodically for re-keying
independent_segments E........ add EXT-X-INDEPENDENT-SEGMENTS, whenever applicable
-use_localtime E........ set filename expansion with strftime at segment creation(will be deprecated ) (default false)
-strftime E........ set filename expansion with strftime at segment creation (default false)
-use_localtime_mkdir E........ create last directory component in strftime-generated filename(will be deprecated) (default false)
-strftime_mkdir E........ create last directory component in strftime-generated filename (default false)
-hls_playlist_type E........ set the HLS playlist type (from 0 to 2) (default 0)
event E........ EVENT playlist
vod E........ VOD playlist
-method E........ set the HTTP method(default: PUT)
-hls_start_number_source E........ set source of first number in sequence (from 0 to 2) (default generic)
generic E........ start_number value (default)
epoch E........ seconds since epoch
datetime E........ current datetime as YYYYMMDDhhmmss
-http_user_agent E........ override User-Agent field in HTTP header
-var_stream_map E........ Variant stream map string
-cc_stream_map E........ Closed captions stream map string
-master_pl_name E........ Create HLS master playlist with this name
-master_pl_publish_rate E........ Publish master play list every after this many segment intervals (from 0 to UINT32_MAX) (default 0)
-http_persistent E........ Use persistent HTTP connections (default false)
-timeout E........ set timeout for socket I/O operations (default -0.000001)
-ignore_io_errors E........ Ignore IO errors for stable long-duration runs with network output (default false)