On Mon, Nov 18, 2019 at 10:37 AM gordon <[email protected]> wrote: > Okay, thank you. I will give that a go. > > -- aside -- > > I thought that the "-force_key_frames expr:gte(t,n_forced*2)" was placing > the key frames for segment boundaries and still allowing the encoder to > place other keyframes where they wanted? I am trying to use h264, h265, > and vp9 so I figured the keyframes not at boundaries would need to be > different for efficiency. > > How do I determine the best (or good) value for "-g" given a particular > source file and target duration for segments? > > On Mon, Nov 18, 2019 at 10:19 AM Dennis Mungai <[email protected]> wrote: > >> On Mon, 18 Nov 2019 at 17:31, gordon <[email protected]> wrote: >> >> > Why are the segments for my stream not aligned? The first command >> outputs >> > video segment. The second command outputs an audio segment with the >> > previous video output copied in. >> > >> > Ffmpeg commands are pasted below with the m3u8 outputs. The same >> results >> > were observed on ffmpeg 4.2.1 and snapshot >> > >> > /usr/local/bin/ffmpeg -y -loglevel error -f rawvideo -vcodec rawvideo -s >> > 160x120 -pix_fmt rgb24 -r 12.00 -i - -an -vcodec libx264 -preset medium >> -f >> > hls -an -hls_flags single_file -hls_time 6 -hls_list_size 0 >> > -hls_segment_type mpegts -hls_segment_filename >> > >> > >> /tmp/973b7b02b6e6486f90d3064527a69701/output/21b79578a1d04533932e32d28f46eb94.ts >> > -hls_playlist_type vod -master_pl_name >> > 21b79578a1d04533932e32d28f46eb94-master.m3u8 -force_key_frames >> > 'expr:gte(t,n_forced*2)' -profile:v baseline -level 3.0 -pix_fmt yuv420p >> > -vsync cfr -b 145k -pix_fmt yuv420p >> > >> > >> /tmp/973b7b02b6e6486f90d3064527a69701/output/21b79578a1d04533932e32d28f46eb94-variant.m3u8 >> > >> > #EXTM3U >> > #EXT-X-VERSION:4 >> > #EXT-X-TARGETDURATION:6 >> > #EXT-X-MEDIA-SEQUENCE:0 >> > #EXT-X-PLAYLIST-TYPE:VOD >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:116748@0 >> > 21b79578a1d04533932e32d28f46eb94.ts >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:96256@116748 >> > 21b79578a1d04533932e32d28f46eb94.ts >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:143256@213004 >> > 21b79578a1d04533932e32d28f46eb94.ts >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:97760@356260 >> > 21b79578a1d04533932e32d28f46eb94.ts >> > #EXTINF:5.750000, >> > #EXT-X-BYTERANGE:75764@454020 >> > 21b79578a1d04533932e32d28f46eb94.ts >> > #EXT-X-ENDLIST >> > >> > >> > /usr/local/bin/ffmpeg -y -loglevel error -f s16le -acodec pcm_s16le -ar >> > 44100 -ac 2 -i - -i >> > >> > >> /tmp/973b7b02b6e6486f90d3064527a69701/output/21b79578a1d04533932e32d28f46eb94.ts >> > -vcodec copy -acodec libfdk_aac -ar 44100 -strict -2 -profile:a >> aac_he_v2 >> > -vbr 1 -f hls -hls_flags single_file -hls_time 6 -hls_list_size 0 >> > -hls_segment_type mpegts -hls_segment_filename >> > >> > >> /tmp/973b7b02b6e6486f90d3064527a69701/output/e3658a88388c4d4da25681956bccb00f.ts >> > -hls_playlist_type vod -master_pl_name >> > e3658a88388c4d4da25681956bccb00f-master.m3u8 -force_key_frames >> > 'expr:gte(t,n_forced*2)' -pix_fmt yuv420p -vsync cfr >> > >> > >> /tmp/973b7b02b6e6486f90d3064527a69701/output/e3658a88388c4d4da25681956bccb00f-variant.m3u8 >> > >> > #EXTM3U >> > #EXT-X-VERSION:4 >> > #EXT-X-TARGETDURATION:6 >> > #EXT-X-MEDIA-SEQUENCE:0 >> > #EXT-X-PLAYLIST-TYPE:VOD >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:146452@0 >> > e3658a88388c4d4da25681956bccb00f.ts >> > #EXTINF:6.000000, >> > #EXT-X-BYTERANGE:125020@146452 >> > e3658a88388c4d4da25681956bccb00f.ts >> > #EXTINF:5.916667, >> > #EXT-X-BYTERANGE:167320@271472 >> > e3658a88388c4d4da25681956bccb00f.ts >> > #EXTINF:6.083333, >> > #EXT-X-BYTERANGE:133856@438792 >> > e3658a88388c4d4da25681956bccb00f.ts >> > #EXTINF:5.750000, >> > #EXT-X-BYTERANGE:103776@572648 >> > e3658a88388c4d4da25681956bccb00f.ts >> > #EXT-X-ENDLIST >> >> >> >> To ensure alignment, you must use a closed GOP (set via -flags +cgop) and >> specify a GOP size via the -g option passed to your video encoder. >> >> > >> > >> _______________________________________________ >> ffmpeg-user mailing list >> [email protected] >> https://ffmpeg.org/mailman/listinfo/ffmpeg-user >> >> To unsubscribe, visit link above, or email >> [email protected] with subject "unsubscribe". > >
Sorry for the top post - gmail does that by default. I've copied my reply below for ease of reading: Okay, thank you. I will give that a go. -- aside -- I thought that the "-force_key_frames expr:gte(t,n_forced*2)" was placing the key frames for segment boundaries and still allowing the encoder to place other keyframes where they wanted? I am trying to use h264, h265, and vp9 so I figured the keyframes not at boundaries would need to be different for efficiency. How do I determine the best (or good) value for "-g" given a particular source file and target duration for segments? _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
