[FFmpeg-devel] [PATCH] lavf: increase probesize

[Michael Niedermayer]

On Wed, Oct 17, 2012 at 10:13:58PM -0700, James Zern wrote:
> On Tue, Oct 16, 2012 at 11:49 PM, Reimar Döffinger
> <Reimar.Doeffinger at gmx.de> wrote:
> > On 17 Oct 2012, at 04:19, James Zern <jzern at google.com> wrote:
> >
> >> On Tue, Oct 16, 2012 at 7:17 PM, James Zern <jzern at google.com> wrote:
> >>> ---
> >>> libavformat/options_table.h |    2 +-
> >>> 1 files changed, 1 insertions(+), 1 deletions(-)
> >>>
> >>> diff --git a/libavformat/options_table.h b/libavformat/options_table.h
> >>> index 778c740..29ee8cd 100644
> >>> --- a/libavformat/options_table.h
> >>> +++ b/libavformat/options_table.h
> >>> @@ -35,7 +35,7 @@
> >>> static const AVOption options[]={
> >>> {"avioflags", NULL, OFFSET(avio_flags), AV_OPT_TYPE_FLAGS, {.i64 = DEFAULT }, INT_MIN, INT_MAX, D|E, "avioflags"},
> >>> {"direct", "reduce buffering", 0, AV_OPT_TYPE_CONST, {.i64 = AVIO_FLAG_DIRECT }, INT_MIN, INT_MAX, D|E, "avioflags"},
> >>> -{"probesize", "set probing size", OFFSET(probesize), AV_OPT_TYPE_INT, {.i64 = 5000000 }, 32, INT_MAX, D},
> >>> +{"probesize", "set probing size", OFFSET(probesize), AV_OPT_TYPE_INT, {.i64 = 10000000 }, 32, INT_MAX, D},
> >>> {"packetsize", "set packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, E},
> >>> {"fflags", NULL, OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = DEFAULT }, INT_MIN, INT_MAX, D|E, "fflags"},
> >>> {"ignidx", "ignore index", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_IGNIDX }, INT_MIN, INT_MAX, D, "fflags"},
> >>> --
> >>> 1.7.7.3
> >>>
> >>
> >> This is arbitrary, but I thought I'd send it around for discussion
> >> before updating code locally.
> >> The background: I was doing some 4K encodes and found that I could end
> >> up with initial video frames > 5MB, which would result in no audio
> >> information being reported.
> >
> > This can delay playback of low bitrate streamed content a lot I believe.
> 
> Assuming the file has header information, wouldn't find_stream_info
> break out early?

I think we should use a (byte based) probesize only when no time or
duration based information is available.
streams can vary alot from a few kilobits per second to several
gigabyte per second, a limit based on bytes inevitably has to allow
the higher end while causing unacceptable delays on the lower end


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20121018/f59d0c4d/attachment.asc>