[FFmpeg-devel] [RFC][PATCH] ticks_per_frame / timebase

[Michael Niedermayer]

On Thu, Feb 26, 2009 at 02:46:36PM -0800, Baptiste Coudurier wrote:
> Michael Niedermayer wrote:
> > On Thu, Feb 26, 2009 at 02:18:41PM -0800, Baptiste Coudurier wrote:
> >> Hi guys,
> >>
> >> Michael Niedermayer wrote:
> >>> On Thu, Feb 26, 2009 at 10:05:28PM +0100, Ivan Schreter wrote:
> >>>> Michael Niedermayer wrote:
> >>>>> [...]
> >>>>> also i think the reset of the sei vars should be in
> >>>>> decode_nal_units()
> >>>>> ...
> >>>>>     if(!(s->flags2 & CODEC_FLAG2_CHUNKS)){
> >>>>>         h->current_slice = 0;
> >>>>>         if (!s->first_field)
> >>>>>             s->current_picture_ptr= NULL;
> >>>>>         <-----------------------here
> >>>>>     }
> >>>>>
> >>>>> the reason is that just reseting at the end of a pic is "risky" if that 
> >>>>> end
> >>>>> isnt reached
> >>>>>
> >>>>>   
> >>>> Like in the attached patch?
> >>> yes, patch ok
> >>>
> >>> btw, if you want a svn write account, (and agree to the devel/svn policy
> >>> and split patches a little more, this one should be
> >>> factorizing the code and then seperately adding the new call)
> >>> then send diego b. some username & password gpg encrypted
> >>>
> >> Applied both patches:
> >>
> >> ffmpeg -i h264.mp4 -vcodec copy test.mov
> >>
> >> Seems stream 1 codec frame rate differs from container frame rate: 12.50
> >> (25/2) -> 25.00 (25/1)
> >> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'H264.mp4':
> >>   Duration: 00:00:02.18, start: 0.000000, bitrate: 2245 kb/s
> >>     Stream #0.0(eng): Audio: aac, 44100 Hz, stereo, s16
> >>     Stream #0.1(eng): Video: h264, yuv420p, 720x576, 25 tbr, 25 tbn, 25 tbc
> >> File 'test.mov' already exists. Overwrite ? [y/N] y
> >> Output #0, mov, to 'test.mov':
> >>     Stream #0.0(eng): Video: libx264, yuv420p, 720x576, q=2-31, 90k tbn,
> >> 25 tbc
> >>     Stream #0.1(eng): Audio: libfaac, 44100 Hz, stereo, s16, 64 kb/s
> >>
> >> Is this supposed to report 12.50 ?
> > 
> > no, ive droped the hunk that messed with the printing in ffmpeg.c locally
> > is the nonsense it prints the only problem? or are there other problems?
> > 
> 
> It seems ok, however it does not do the same for MPEG-2 when I stream copy:
> 
> Seems stream 0 codec frame rate differs from container frame rate: 25.00
> (50/2) -> 25.00 (25/1)
> Input #0, mpeg, from 'PubMatrix.mpg':
>   Duration: 00:00:24.26, start: 0.220000, bitrate: 11888 kb/s
>     Stream #0.0[0x1e0]: Video: mpeg2video, yuv422p, 720x608 [PAR 1:1 DAR
> 45:38], 11386 kb/s, 25 tbr, 90k tbn, 50 tbc
>     Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16, 384 kb/s
> File 'test.mov' already exists. Overwrite ? [y/N] y
> Output #0, mov, to 'test.mov':
>     Stream #0.0: Video: mpeg2video, yuv422p, 720x608 [PAR 1:1 DAR
> 45:38], q=2-31, 11386 kb/s, 90k tbn, 50 tbc
>     Stream #0.1: Audio: libfaac, 48000 Hz, stereo, s16, 64 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> 
> In this case pkt->duration is 2 and timebase.den is 50, with H.264
> pkt->duration is 1 and timebase.den is 25, is this normal ? Can't we get
> 1 and 1/25 with MPEG-2 too ?

yes, the following hunk does that:
@@ -1750,9 +1751,10 @@
             codec->bit_rate = icodec->bit_rate;
             codec->extradata= icodec->extradata;
             codec->extradata_size= icodec->extradata_size;
-            if(av_q2d(icodec->time_base) > av_q2d(ist->st->time_base) && av_q2d(ist->st->time_base) < 1.0/1000)
+            if(av_q2d(icodec->time_base)*icodec->ticks_per_frame > av_q2d(ist->st->time_base) && av_q2d(ist->st->time_base) < 1.0/1000){
                 codec->time_base = icodec->time_base;
-            else
+                codec->time_base.num *= icodec->ticks_per_frame;
+            }else
                 codec->time_base = ist->st->time_base;
             switch(codec->codec_type) {
             case CODEC_TYPE_AUDIO:


more issues left before i can commit it?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Thouse who are best at talking, realize last or never when they are wrong.
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