Re: [FFmpeg-devel] [PATCH 3/3] avcodec/pngenc: write eXIf chunks
On 2/14/24 13:53, Andreas Rheinhardt wrote:
Leo Izen:
Write EXIF metadata exposed AV_FRAME_DATA_EXIF as an eXIf chunk
to PNG files, if present.
Signed-off-by: Leo Izen
---
libavcodec/pngenc.c | 4
1 file changed, 4 insertions(+)
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 50689cb50c..a302c879da 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -413,6 +413,10 @@ static int encode_headers(AVCodecContext *avctx, const
AVFrame *pict)
}
}
+side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_EXIF);
+if (side_data)
+png_write_chunk(>bytestream, MKTAG('e', 'X', 'I', 'f'),
side_data->data, FFMIN(side_data->size, INT_MAX));
+
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
if ((ret = png_write_iccp(s, side_data)))
return ret;
If I see this correctly, then these patches can lead to a situation
where an input packet has rotation metadata in exif which gets exported
twice -- as displaymatrix and as exif metadata side data. If the user
changes the displaymatrix (e.g. applies the transformation to the image
data and removes the displaymatrix side data before reencoding), the
exif data (that the user would probably not be aware of) would still be
there and get propagated into the output, corrupting it.
Hm. This is true, but it's also currently how the mjpeg decoder
functions (i.e. it attaches displaymatrix side data).
There are no encoders that currently save EXIF metadata, so there's no
precedent.
How do you suggest this be reconciled?
- Leo Izen (Traneptora)
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Re: [FFmpeg-devel] [PATCH 3/3] avcodec/pngenc: write eXIf chunks
Leo Izen:
> Write EXIF metadata exposed AV_FRAME_DATA_EXIF as an eXIf chunk
> to PNG files, if present.
>
> Signed-off-by: Leo Izen
> ---
> libavcodec/pngenc.c | 4
> 1 file changed, 4 insertions(+)
>
> diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
> index 50689cb50c..a302c879da 100644
> --- a/libavcodec/pngenc.c
> +++ b/libavcodec/pngenc.c
> @@ -413,6 +413,10 @@ static int encode_headers(AVCodecContext *avctx, const
> AVFrame *pict)
> }
> }
>
> +side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_EXIF);
> +if (side_data)
> +png_write_chunk(>bytestream, MKTAG('e', 'X', 'I', 'f'),
> side_data->data, FFMIN(side_data->size, INT_MAX));
> +
> side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
> if ((ret = png_write_iccp(s, side_data)))
> return ret;
If I see this correctly, then these patches can lead to a situation
where an input packet has rotation metadata in exif which gets exported
twice -- as displaymatrix and as exif metadata side data. If the user
changes the displaymatrix (e.g. applies the transformation to the image
data and removes the displaymatrix side data before reencoding), the
exif data (that the user would probably not be aware of) would still be
there and get propagated into the output, corrupting it.
- Andreas
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Re: [FFmpeg-devel] [PATCH 3/3] avcodec/pngenc: write eXIf chunks
On Tue, Feb 13, 2024 at 04:24:56PM -0500, Leo Izen wrote: > Write EXIF metadata exposed AV_FRAME_DATA_EXIF as an eXIf chunk > to PNG files, if present. > > Signed-off-by: Leo Izen > --- > libavcodec/pngenc.c | 4 > 1 file changed, 4 insertions(+) This seems to break: --- ./tests/ref/fate/cover-art-mp3-id3v2-remux 2024-02-14 19:33:50.756012174 +0100 +++ tests/data/fate/cover-art-mp3-id3v2-remux 2024-02-14 19:36:59.150052682 +0100 @@ -1,5 +1,5 @@ -94946f0efd5f9bb0061ac1fbff7d731f *tests/data/fate/cover-art-mp3-id3v2-remux.mp3 -399346 tests/data/fate/cover-art-mp3-id3v2-remux.mp3 +0643e306430fbadeb1c89da6ab36a303 *tests/data/fate/cover-art-mp3-id3v2-remux.mp3 +399414 tests/data/fate/cover-art-mp3-id3v2-remux.mp3 #tb 0: 1/14112000 #media_type 0: audio #codec_id 0: mp3 @@ -23,7 +23,7 @@ 0,-353590,-353590, 368640, 417, 0x15848290, S=1, 10 1, 0, 0,0, 208350, 0x291b44d1 2, 0, 0,0,15760, 0x71d5c418 -3, 0, 0,0, 165671, 0x7c1c8070 +3, 0, 0,0, 165739, 0x2e108b69 0, 15050, 15050, 368640, 418, 0x46f684a4 0, 383690, 383690, 368640, 418, 0x46f684a4 0, 752330, 752330, 368640, 418, 0x46f684a4 Test cover-art-mp3-id3v2-remux failed. Look at tests/data/fate/cover-art-mp3-id3v2-remux.err for details. tests/Makefile:318: recipe for target 'fate-cover-art-mp3-id3v2-remux' failed make: *** [fate-cover-art-mp3-id3v2-remux] Error 1 [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Opposition brings concord. Out of discord comes the fairest harmony. -- Heraclitus signature.asc Description: PGP signature ___ 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".
[FFmpeg-devel] [PATCH 3/3] avcodec/pngenc: write eXIf chunks
Write EXIF metadata exposed AV_FRAME_DATA_EXIF as an eXIf chunk
to PNG files, if present.
Signed-off-by: Leo Izen
---
libavcodec/pngenc.c | 4
1 file changed, 4 insertions(+)
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 50689cb50c..a302c879da 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -413,6 +413,10 @@ static int encode_headers(AVCodecContext *avctx, const
AVFrame *pict)
}
}
+side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_EXIF);
+if (side_data)
+png_write_chunk(>bytestream, MKTAG('e', 'X', 'I', 'f'),
side_data->data, FFMIN(side_data->size, INT_MAX));
+
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
if ((ret = png_write_iccp(s, side_data)))
return ret;
--
2.43.0
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