[FFmpeg-devel] [PATCH 2/7] avcodec/ffv1enc: add information message when version is changed by the encoder

[Michael Niedermayer]

On Thu, Mar 08, 2018 at 03:12:26AM +0100, Jerome Martinez wrote:
> On 08/03/2018 01:33, Michael Niedermayer wrote:
> >On Wed, Mar 07, 2018 at 04:49:24PM +0100, Jerome Martinez wrote:
> >>There is a message when coder type is forced to a value not chosen by user,
> >>but no message when version is forced to a value not chosen by user.
> >>This patch adds such message for more coherency in the messages, and the
> >>user is informed that the command is not fully respected.
> >>
> >>ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
> >>-level 0 -coder 0 a.mkv
> >>
> >>Before:
> >>[ffv1 @ 000002492CD69B40] bits_per_raw_sample > 8, forcing range coder
> >>
> >>After:
> >>[ffv1 @ 000001A6E404A780] bits_per_raw_sample > 8, forcing version 1
> >>[ffv1 @ 000001A6E404A780] bits_per_raw_sample > 8, forcing range coder
> >>
> >>
> >>  ffv1enc.c |    8 +++++++-
> >>  1 file changed, 7 insertions(+), 1 deletion(-)
> >>cb1df919e21fe4d388df7de9349c5c2c46777862  0002-avcodec-ffv1enc-add-information-message-when-version.patch
> >> From 49db6049fa50976683fc651cf180ab8c7428225e Mon Sep 17 00:00:00 2001
> >>From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Martinez?= <jerome at mediaarea.net>
> >>Date: Wed, 7 Mar 2018 10:37:46 +0100
> >>Subject: [PATCH 2/7] avcodec/ffv1enc: add information message when version is
> >>  changed by the encoder
> >>
> >>---
> >>  libavcodec/ffv1enc.c | 8 +++++++-
> >>  1 file changed, 7 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/libavcodec/ffv1enc.c b/libavcodec/ffv1enc.c
> >>index d71d952c6d..ac8b715b74 100644
> >>--- a/libavcodec/ffv1enc.c
> >>+++ b/libavcodec/ffv1enc.c
> >>@@ -509,7 +509,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
> >>  {
> >>      FFV1Context *s = avctx->priv_data;
> >>      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
> >>-    int i, j, k, m, ret;
> >>+    int i, j, k, m, ret, oldversion;
> >>      if ((ret = ff_ffv1_common_init(avctx)) < 0)
> >>          return ret;
> >>@@ -534,6 +534,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
> >>          }
> >>          s->version = avctx->level;
> >>      }
> >>+    oldversion = s->version;
> >>      if (s->ec < 0) {
> >>          s->ec = (s->version >= 3);
> >>@@ -679,6 +680,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
> >>      av_assert0(s->bits_per_raw_sample >= 8);
> >>      if (s->bits_per_raw_sample > 8) {
> >>+        if (oldversion >= 0 && oldversion != s->version) {
> >>+            av_log(avctx, AV_LOG_INFO,
> >>+                    "bits_per_raw_sample > 8, forcing version 1\n");
> >>+            oldversion = s->version;
> >>+        }
> >I dont think this works consistently
> >
> >The code does not seem to be limited to the case where the user has
> >specifified a version for example unless i miss something
> 
> checking range coder part, I see that currently there is actually a slight
> difference with the other AV_LOG_INFO, I don't indicate the message when
> level is not indicated, as I didn't see the value added of such information
> when level is not indicated on the command line when I implemented the test.
> 
> With patch proposal:
> 
> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
> a.mkv
> [ffv1 @ 00000232D35B9240] bits_per_raw_sample > 8, forcing range coder
> (no change)
> 
> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
> -coder 0 a.mkv
> [ffv1 @ 0000014B9B1771C0] bits_per_raw_sample > 8, forcing range coder
> (no change)
> 
> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
> -level 0 a.mkv
> [ffv1 @ 000001BC2B881500] bits_per_raw_sample > 8, forcing version 1
> [ffv1 @ 000001BC2B881500] bits_per_raw_sample > 8, forcing range coder
> ("version 1" line added because user specified version 0, IMO encoder should
> inform user that this is not respected)
> 
> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
> -level 0 -coder 0 a.mkv
> [ffv1 @ 000001EAC7685180] bits_per_raw_sample > 8, forcing version 1
> [ffv1 @ 000001EAC7685180] bits_per_raw_sample > 8, forcing range coder
> ("version 1" line added because user specified version 0, IMO encoder should
> inform user that this is not respected)

I have the suspicion there are more corner cases that behave odd, but ive
no time ATM to test, ill do that tomorrow unless i forget


> 
> Just for being clear: do you want info message also when level/version is
> *not* indicated on the command line?

some sort of debug level message indicating the version may be usefull
if theres nothing showing it currently

at higher level i think it should only be shown if its worth it to the
user like for example if it overrides what was speified or somehow has
compatibility issues

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

Freedom in capitalist society always remains about the same as it was in
ancient Greek republics: Freedom for slave owners. -- Vladimir Lenin
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