| Message ID | 58A1B17C.1090607@email.cz |
|---|---|
| State | New |
| Headers | show |
2017-02-13 21:15 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: > This patch will fix cutting hls segments into exactly same length. Because > it will intialize only on first ref_packet, which is video frame, not audio > frame (old behavior) > > Now it should be possible to create segments at exactly same length if we > use new -force_key_frames hls:time_in_seconds parameter. > > This is required to support adaptive HLS. > > This patch was splitted to two parts, this is first independent part > > -- > Miroslav Slugeň > > > > > > > > > > > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > Patch can compile passed, but i cannot reproduce the problem before your patch, can you send a reproduce step and test file?
Dne 14.2.2017 v 04:59 Steven Liu napsal(a): > 2017-02-13 21:15 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: > >> This patch will fix cutting hls segments into exactly same length. Because >> it will intialize only on first ref_packet, which is video frame, not audio >> frame (old behavior) >> >> Now it should be possible to create segments at exactly same length if we >> use new -force_key_frames hls:time_in_seconds parameter. >> >> This is required to support adaptive HLS. >> >> This patch was splitted to two parts, this is first independent part >> >> -- >> Miroslav Slugeň >> >> >> >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> > Patch can compile passed, but i cannot reproduce the problem before your > patch, can you send a reproduce step and test file? > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel I can provide you with sample. But this explanation should be enough: When you use -copyts for long time audio/video sync when transcoding from MPEGTS stream, audio comes always sooner than video (it is around 1-2 s), so hlsenc is initialized with audio packet PTS instead of video packet PTS. That is not correct if you wan't to have all segments with same length -forced_keyframes to force keyframe at video position. Every other calculations of hls_time is done only on ref_packets which is video. This scenario is problematic when encoder is also inserting keyframes by its own decision (libx264 default behavior). M.
2017-02-14 16:30 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: > Dne 14.2.2017 v 04:59 Steven Liu napsal(a): > > 2017-02-13 21:15 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: >> >> This patch will fix cutting hls segments into exactly same length. Because >>> it will intialize only on first ref_packet, which is video frame, not >>> audio >>> frame (old behavior) >>> >>> Now it should be possible to create segments at exactly same length if we >>> use new -force_key_frames hls:time_in_seconds parameter. >>> >>> This is required to support adaptive HLS. >>> >>> This patch was splitted to two parts, this is first independent part >>> >>> -- >>> Miroslav Slugeň >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> ffmpeg-devel mailing list >>> ffmpeg-devel@ffmpeg.org >>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >>> >>> >>> Patch can compile passed, but i cannot reproduce the problem before your >> patch, can you send a reproduce step and test file? >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> > I can provide you with sample. But this explanation should be enough: > > When you use -copyts for long time audio/video sync when transcoding from > MPEGTS stream, audio comes always sooner than video (it is around 1-2 s), > so hlsenc is initialized with audio packet PTS instead of video packet PTS. > That is not correct if you wan't to have all segments with same length > -forced_keyframes to force keyframe at video position. Every other > calculations of hls_time is done only on ref_packets which is video. This > scenario is problematic when encoder is also inserting keyframes by its own > decision (libx264 default behavior). command line please! > > > M. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >
Dne 14.2.2017 v 09:33 Steven Liu napsal(a): > 2017-02-14 16:30 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: > >> Dne 14.2.2017 v 04:59 Steven Liu napsal(a): >> >> 2017-02-13 21:15 GMT+08:00 Miroslav Slugeň <thunder.m@email.cz>: >>> This patch will fix cutting hls segments into exactly same length. Because >>>> it will intialize only on first ref_packet, which is video frame, not >>>> audio >>>> frame (old behavior) >>>> >>>> Now it should be possible to create segments at exactly same length if we >>>> use new -force_key_frames hls:time_in_seconds parameter. >>>> >>>> This is required to support adaptive HLS. >>>> >>>> This patch was splitted to two parts, this is first independent part >>>> >>>> -- >>>> Miroslav Slugeň >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> ffmpeg-devel mailing list >>>> ffmpeg-devel@ffmpeg.org >>>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >>>> >>>> >>>> Patch can compile passed, but i cannot reproduce the problem before your >>> patch, can you send a reproduce step and test file? >>> _______________________________________________ >>> ffmpeg-devel mailing list >>> ffmpeg-devel@ffmpeg.org >>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >>> >> I can provide you with sample. But this explanation should be enough: >> >> When you use -copyts for long time audio/video sync when transcoding from >> MPEGTS stream, audio comes always sooner than video (it is around 1-2 s), >> so hlsenc is initialized with audio packet PTS instead of video packet PTS. >> That is not correct if you wan't to have all segments with same length >> -forced_keyframes to force keyframe at video position. Every other >> calculations of hls_time is done only on ref_packets which is video. This >> scenario is problematic when encoder is also inserting keyframes by its own >> decision (libx264 default behavior). > command line please! > >> >> M. >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel ffmpeg -i dvb_record.ts \ -map 0:v:0 -filter:v yadif -force_key_frames 'expr:gte(t,n_forced*10)' -c:v libx264 -g 250 -b:v 500k \ -map 0:a:0 -ac 2 -ar 48000 -c:a libfdk_aac -b:a 128k \ -sn \ -copyts \ -r 25 \ -hls_time 10 -hls_list_size 10 -hls_allow_cache 1 -use_localtime 1 -hls_flags omit_endlist+discont_start \ -hls_segment_filename "segment-%Y%m%d-%s.ts" -f hls -y "playlist.m3u8" But this will not work correctly until -force_key_frames is fixed for copyts, or until you use -force_key_frames hls:10 from my patch "[PATCH] ffmpeg: add new forced_keyframes option hls:time" M.
From 2d0bbf0a68bc5f85f24c65a65e3ae70c362e82dc Mon Sep 17 00:00:00 2001 From: Miroslav Slugen <thunder.m@email.cz> Date: Mon, 13 Feb 2017 14:13:18 +0100 Subject: [PATCH 1/1] hlsenc: intialize only on ref_pkt --- libavformat/hlsenc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c index 930e94b..e107fff 100644 --- a/libavformat/hlsenc.c +++ b/libavformat/hlsenc.c @@ -1279,10 +1279,6 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt) oc = hls->avf; stream_index = pkt->stream_index; } - if (hls->start_pts == AV_NOPTS_VALUE) { - hls->start_pts = pkt->pts; - hls->end_pts = pkt->pts; - } if (hls->has_video) { can_split = st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && @@ -1293,6 +1289,11 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt) is_ref_pkt = can_split = 0; if (is_ref_pkt) { + if (hls->start_pts == AV_NOPTS_VALUE) { + hls->start_pts = pkt->pts; + hls->end_pts = pkt->pts; + } + if (hls->new_start) { hls->new_start = 0; hls->duration = (double)(pkt->pts - hls->end_pts) -- 2.1.4