On Wed, Mar 07, 2018 at 11:37:00PM +0000, Josh Allmann wrote:
> On 7 March 2018 at 18:03, Michael Niedermayer <mich...@niedermayer.cc> wrote:
> > On Tue, Mar 06, 2018 at 12:47:15PM -0800, Josh Allmann wrote:
> >> ---
> >> doc/bitstream_filters.texi | 5 +++++
> >> libavcodec/noise_bsf.c | 12 ++++++++++++
> >> libavcodec/version.h | 2 +-
> >> 3 files changed, 18 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
> >> index cfd81fa12d..a9f17f32ec 100644
> >> --- a/doc/bitstream_filters.texi
> >> +++ b/doc/bitstream_filters.texi
> >> @@ -399,6 +399,11 @@ every byte is modified.
> >> A numeral string, whose value is related to how often packets will be
> >> dropped.
> >> Therefore, values below or equal to 0 are forbidden, and the lower the
> >> more
> >> frequent packets will be dropped, with 1 meaning every packet is dropped.
> >> +@item keyframes
> >> +A numeral string, whose value indicates the number of keyframe packets
> >> that
> >> +will be dropped from the beginning of the stream. This option will not add
> >> +noise to the source data. If used with stream copy, then -copyinkf should
> >> +be added to the output options as well.
> >> @end table
> >>
> >> The following example applies the modification to every byte but does not
> >> drop
> >> diff --git a/libavcodec/noise_bsf.c b/libavcodec/noise_bsf.c
> >> index 84b94032ad..363ea4fc71 100644
> >> --- a/libavcodec/noise_bsf.c
> >> +++ b/libavcodec/noise_bsf.c
> >> @@ -32,6 +32,7 @@ typedef struct NoiseContext {
> >> const AVClass *class;
> >> int amount;
> >> int dropamount;
> >> + int keyframes;
> >> unsigned int state;
> >> } NoiseContext;
> >>
> >> @@ -49,6 +50,13 @@ static int noise(AVBSFContext *ctx, AVPacket *out)
> >> if (ret < 0)
> >> return ret;
> >>
> >> + if (s->keyframes > 0 && in->flags & AV_PKT_FLAG_KEY) {
> >> + s->keyframes--;
> >> + if (!s->keyframes) s->keyframes = -1;
> >> + av_packet_free(&in);
> >> + return AVERROR(EAGAIN);
> >> + }
> >
>
> Thanks for the feedback.
> > > I think keyframe should work like dropamount, that is randomly. > > > > a non random droping could be added, maybe by the user specifying in > > a list what to drop. > > That would be more powerfull and flexible but probably not much harder > > Something like this? > > noise=keyframes=1,3,5,7 > > in order to drop the 1st, 3rd, 5th and 7th keyframes? yes something like this > > > also keeping keyframes and dropamount behave the same > > is more consistent > > > > Do you mean more consistent with respect to the 'amount' param of added noise, > as opposed to the patch's behavior of skipping noise if the 'keyframes' param > is > present? both. i meant the param but as you mention the skiping, that doesnt seem expected by a user either so it likely would be confusing. thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB It is dangerous to be right in matters on which the established authorities are wrong. -- Voltaire
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