On 2021-07-24 09:55, Andreas Rheinhardt wrote:
Gyan Doshi:
On 2021-07-24 03:19, Michael Niedermayer wrote:
On Sat, Jul 24, 2021 at 01:24:54AM +0530, Gyan Doshi wrote:
On 2021-07-24 01:14, Michael Niedermayer wrote:
On Fri, Jul 23, 2021 at 04:04:49PM +0530, Gyan Doshi wrote:
Currently, the user is forced to accept some noise in
packet payload, even if not requested.
---
doc/bitstream_filters.texi | 13 +++++-------
libavcodec/noise_bsf.c | 21
+++++++++++++------
tests/fate/matroska.mak | 2 +-
.../fate/matroska-mastering-display-metadata | 10 ++++-----
4 files changed, 26 insertions(+), 20 deletions(-)
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index d10842ae47..2b84bda1fc 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -534,20 +534,17 @@ container. Can be used for fuzzing or testing
error resilience/concealment.
Parameters:
@table @option
@item amount
-A numeral string, whose value is related to how often output bytes
will
-be modified. Therefore, values below or equal to 0 are forbidden, and
-the lower the more frequent bytes will be modified, with 1 meaning
-every byte is modified.
+Accepts a positive integer. Lower the value, more frequently bytes
will be modified,
+with @var{1} meaning every byte is modified. Default is @var{0}.
@item dropamount
-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.
+Accepts a positive integer. Lower the value, more frequently
packets will be dropped,
+with @var{1} meaning every packet is dropped. Default is @var{0}.
@end table
The following example applies the modification to every byte but
does not drop
any packets.
@example
-ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
+ffmpeg -i INPUT -c copy -bsf noise=amount=1 output.mkv
@end example
@section null
diff --git a/libavcodec/noise_bsf.c b/libavcodec/noise_bsf.c
index 6ebd369633..c1b0203442 100644
--- a/libavcodec/noise_bsf.c
+++ b/libavcodec/noise_bsf.c
@@ -33,20 +33,28 @@ typedef struct NoiseContext {
unsigned int state;
} NoiseContext;
-static int noise(AVBSFContext *ctx, AVPacket *pkt)
+static int noise_init(AVBSFContext *ctx)
{
NoiseContext *s = ctx->priv_data;
- int amount = s->amount > 0 ? s->amount : (s->state % 10001 + 1);
- int i, ret;
you are droping the support for variable noise
this also breaks a simple plain "-bsf noise"
Will re-add it. Is making it default required?
what else would -bsf noise do ?
Originally, noise could only alter packet data, so it made sense that
even with the default of amount=0. the filter shouldn't be a no-op,
despite the intuitive semantics of amount=0 being no alteration .
Once dropping packets was added, there can't be an expectation that with
amount=0. the user still wants to alter data. After all, the opt parser
cannot distinguish between `-bsf noise` and `-bsf
noise=amount=0[:dropamount=non-zero]`. This is how many other filters
work - the default behaviour for setpts, scale, select, crop, pad..etc
is a no-op not some arbitrary adjustment to the payload. That's not good
UX.
Wrong: You can just set the default value of amount to -1 (meaning auto)
which uses the current behaviour for zero. This is not an API change
given that the doc disallowed setting amount to zero. Then one can allow
(and document) setting amount to zero (in the sense that packets that
are not dropped are unchanged).
I did intend to add -1 within the current range for amount. But I was
talking about UX, not whether the current behaviour could be remapped to
a new implicit default.
Regards,
Gyan
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
