[FFmpeg-user] apple-friendly timestamps with -c copy

[Claudiu Rad]

hello warriors,

so maybe this is obvious for some but not for me.

i have some recordings produced by adobe's flash media server 
technologies, encoding originally done by their flash media live encoder 
in h264 + mp3/aac.
only some of them exhibit a bad playback behavior when trying to -c copy 
them to mp4/HLS.
bad playback means stuttering in some players like the fps went down, 
but on apple playing runtimes i really don't know the term or how to 
describe it, it's like the image jumps forward/backward a few frames a 
couple of times per second while the audio runs fine.
apple playing runtimes means: quicktime or safari on os x or iOS playing 
MP4 or HLS generated with ffmpeg.

from my initial investigations, the difference between a well behaving 
adobe recording and a badly behaving one is related to PTS/DTS values, 
visually i guess its like apple plays back based on DTS not PTS, please 
observe how the frames are constantly interlaced:
frame,pkt_pts_time,best_effort_timestamp_time,pkt_dts_time,pict_type
*frame,0.000000,0.040000,0.000000,I*
frame,0.080000,0.080000,0.080000,B
frame,0.120000,0.120000,0.120000,B
frame,0.160000,0.160000,0.160000,B
*frame,0.040000,0.200000,0.200000,P*
frame,0.240000,0.240000,0.240000,B
frame,0.280000,0.280000,0.280000,B
frame,0.320000,0.320000,0.320000,B
*frame,0.200000,0.360000,0.360000,P*
frame,0.400000,0.400000,0.400000,B
...

VLC plays both the original recording and ffmpeg outputs just fine.
if i reencode with ffmpeg everything is then perfect, PTS/DTS are 
aligned, but i want to avoid that.

what ideas do you have? how can i work on timestamps with ffmpeg and 
correct them via -c copy?
basically a reorganizing / re-timestamping so that we have monotonically 
increasing PTS i assume should be enough. is this possible?

a bad recording sample is here: http://www.datafilehost.com/d/6a22a099

ffmpeg output:

ffmpeg -y -i in.f4f -c copy out.mp4
ffmpeg version N-76816-g188a1a1-static Copyright (c) 2000-2015 the 
FFmpeg developers
   built with gcc 4.7 (Debian 4.7.2-5)
   configuration: --prefix=/root/ffmpeg_build 
--extra-cflags='-I/root/ffmpeg_build/include -static' 
--extra-ldflags='-L/root/ffmpeg_build/lib -lm -static' 
--pkg-config-flags=--static --bindir=/root/bin --enable-gpl 
--enable-libfdk-aac --enable-libfreetype --enable-libmp3lame 
--enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx 
--enable-libx264 --enable-libx265 --enable-libxvid --enable-nonfree 
--extra-version=static --disable-debug --disable-shared --enable-static 
--extra-cflags=--static --disable-doc --enable-pthreads 
--enable-postproc --enable-runtime-cpudetect --enable-version3 
--disable-devices
   libavutil      55.  9.100 / 55.  9.100
   libavcodec     57. 16.100 / 57. 16.100
   libavformat    57. 19.100 / 57. 19.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6. 15.100 /  6. 15.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x335fa40] multiple edit list entries, a/v 
desync might occur, patch welcome
     Last message repeated 3 times
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.f4f':
   Metadata:
     major_brand     : f4v
     minor_version   : 1
     compatible_brands: isommp42m4v
     creation_time   : 2015-01-04 18:02:32
   Duration: 00:05:24.98, start: 0.000000, bitrate: 368 kb/s
     Stream #0:0(eng): Data: none (amf0 / 0x30666D61), 0 kb/s (default)
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : MainConcept
     Stream #0:1(eng): Video: h264 (Main) (avc1 / 0x31637661), 
yuv420p(tv), 426x240 [SAR 1:1 DAR 71:40], 200 kb/s, 25 fps, 25 tbr, 1k 
tbn, 50 tbc (default)
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : MainConcept
       encoder         : AVC Coding
     Stream #0:2(eng): Audio: mp3 (.mp3 / 0x33706D2E), 44100 Hz, stereo, 
s16p, 127 kb/s (default)
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : MainConcept
     Stream #0:3(eng): Data: none (rtmp / 0x706D7472), 338 kb/s
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : Adobe Systems Inc. Hint Handler
[mp4 @ 0x34103e0] Codec for stream 0 does not use global headers but 
container format requires global headers
[mp4 @ 0x34103e0] Codec for stream 1 does not use global headers but 
container format requires global headers
Output #0, mp4, to 'out.mp4':
   Metadata:
     major_brand     : f4v
     minor_version   : 1
     compatible_brands: isommp42m4v
     encoder         : Lavf57.19.100
     Stream #0:0(eng): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 
426x240 [SAR 1:1 DAR 71:40], q=2-31, 200 kb/s, 25 fps, 25 tbr, 16k tbn, 
1k tbc (default)
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : MainConcept
       encoder         : AVC Coding
     Stream #0:1(eng): Audio: mp3 (i[0][0][0] / 0x0069), 44100 Hz, 
stereo, 127 kb/s (default)
     Metadata:
       creation_time   : 2015-01-04 18:02:32
       handler_name    : MainConcept
Stream mapping:
   Stream #0:1 -> #0:0 (copy)
   Stream #0:2 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 8125 fps=0.0 q=-1.0 Lsize=   13238kB time=00:05:25.00 bitrate= 
333.7kbits/s
video:7972kB audio:5067kB subtitle:0kB other streams:0kB global 
headers:0kB muxing overhead: 1.525306%

thank you.

-- 
Claudiu