[FFmpeg-devel] [PATCH 1/2] avformat/hlsenc: fix the duration of m4s segment is unusually smaller than expected.

[Liu Steven]

> 在 2018年10月9日，下午4:05，C.H.Liu <liuchh83 at gmail.com> 写道：
> 
> My test clip is big_buck_bunny_1080p_h264.mov with CMD: 
> 
> ./ffmpeg -i ~/Downloads/conversion/big_buck_bunny_1080p_h264.mov -t 50 -flags +cgop -g 30 -preset superfast -f hls -hls_segment_type fmp4 -hls_playlist_type vod -hls_time 10 issue/pl.m3u8
> 
> The original result is:
> 
> #EXTM3U
> #EXT-X-VERSION:7
> #EXT-X-TARGETDURATION:10
> #EXT-X-MEDIA-SEQUENCE:0
> #EXT-X-PLAYLIST-TYPE:VOD
> #EXT-X-MAP:URI="init.mp4"
> #EXTINF:10.416667,
> pl0.m4s
> #EXTINF:1.250000,
> pl1.m4s
> #EXTINF:9.083333,
> pl2.m4s
> #EXTINF:9.791667,
> pl3.m4s
> #EXTINF:10.000000,
> pl4.m4s
> #EXTINF:9.458333,
> pl5.m4s
> #EXT-X-ENDLIST
> 
> 
> 
> After apply the patch, the result become to:
> 
> #EXTM3U
> #EXT-X-VERSION:7
> #EXT-X-TARGETDURATION:10
> #EXT-X-MEDIA-SEQUENCE:0
> #EXT-X-PLAYLIST-TYPE:VOD
> #EXT-X-MAP:URI="init.mp4"
> #EXTINF:10.416667,
> pl0.m4s
> #EXTINF:10.333333,
> pl1.m4s
> #EXTINF:9.791667,
> pl2.m4s
> #EXTINF:10.000000,
> pl3.m4s
> #EXTINF:9.458333,
> pl4.m4s
> #EXT-X-ENDLIST
> 
> 
> 
> Seems that the vs→number in function hls_write_packet() was minus once more. Then “end_pts = hls->recording_time * vs→number;” was too small.
> 
> After having enough buffer (av_compare_ts() around line 2189), we generate the init.mp4 firstly, then the first segment. It should be generate the second segment, when we DO have enough buffer for the second time, . However, the end_pts dons’t grow any, because the vs→number was subtracted 1.
Ok, you are right until now.
fmp4_init_mode maybe you can remove too.



> 
> 
> Liu Steven <lq at chinaffmpeg.org> 于2018年10月9日周二 下午3:28写道：
> 
> 
> > 在 2018年10月9日，下午3:17，Liu Steven <lq at chinaffmpeg.org> 写道：
> > 
> > 
> > 
> >> 在 2018年10月9日，下午2:56，Charles Liu <liuchh83 at gmail.com> 写道：
> >> 
> >> In fmp4 mode, the duration of the second m4s segment is unusually smaller than the expected segment time.
> >> 
> >> Signed-off-by: Charles Liu <liuchh83 at gmail.com>
> >> ---
> >> libavformat/hlsenc.c | 4 ----
> >> 1 file changed, 4 deletions(-)
> >> 
> >> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> >> index 28c2dd62fc..3ccd8756f6 100644
> >> --- a/libavformat/hlsenc.c
> >> +++ b/libavformat/hlsenc.c
> >> @@ -2233,10 +2233,6 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
> >>                }
> >>        }
> >> 
> >> -        if (vs->fmp4_init_mode) {
> >> -            vs->number--;
> >> -        }
> > 
> > No, this is reserve, will be used by byterange mode
> 
> Ah, sorry my mistake, it is because the when the init.mp4 is not in the sequence, so the start number should be 0.
> >> -
> >>        if (hls->segment_type == SEGMENT_TYPE_FMP4) {
> >>            if (hls->flags & HLS_SINGLE_FILE) {
> >>                ret = flush_dynbuf(vs, &range_length);
> >> -- 
> >> 2.19.1
> >> 
> >> _______________________________________________
> >> ffmpeg-devel mailing list
> >> ffmpeg-devel at ffmpeg.org
> >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > 
> > 
> > 
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> > ffmpeg-devel at ffmpeg.org
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> 
> 
> 
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