[FFmpeg-trac] #4321(avfilter:new): Automatically enable alpha channel pixel format on fade with alpha=1
FFmpeg
trac at avcodec.org
Sun Feb 22 19:51:02 CET 2015
#4321: Automatically enable alpha channel pixel format on fade with alpha=1
----------------------------------+---------------------------------------
Reporter: slhck | Type: enhancement
Status: new | Priority: normal
Component: avfilter | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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When you fade in, say, an image as an overlay, and that image has no alpha
channel, it will start fading in from black, even when you set `alpha=1`
in the fade filter.
{{{
$ ffmpeg -i big_buck_bunny_480p_surround-fix.avi -loop 1 -i logo.png \
-filter_complex "[1:v] fade=t=in:st=3:alpha=1 [logo]; \
[0:v][logo] overlay [outv]" \
-map "[outv]" -map 0:a -pix_fmt yuv420p -f matroska - | ffplay -
ffmpeg version 2.5.3 Copyright (c) 2000-2015 the FFmpeg developers
built on Feb 12 2015 19:55:48 with Apple LLVM version 6.0
(clang-600.0.56) (based on LLVM 3.5svn)
configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5.3 --enable-shared
--enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables
--enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-
libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid
--enable-libfontconfig --enable-libfreetype --enable-libtheora --enable-
libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libfaac --enable-libass --enable-
ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac
--enable-openssl --enable-libopus --enable-frei0r --enable-libcaca
--enable-libsoxr --enable-libquvi --enable-libvidstab --enable-libx265
--enable-libopenjpeg --disable-decoder=jpeg2000 --extra-
cflags='-I/usr/local/Cellar/openjpeg/1.5.1_1/include/openjpeg-1.5 '
--enable-nonfree --enable-vda
libavutil 54. 15.100 / 54. 15.100
libavcodec 56. 13.100 / 56. 13.100
libavformat 56. 15.102 / 56. 15.102
libavdevice 56. 3.100 / 56. 3.100
libavfilter 5. 2.103 / 5. 2.103
libavresample 2. 1. 0 / 2. 1. 0
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, avi, from 'big_buck_bunny_480p_surround-fix.avi':
Duration: 00:09:56.46, start: 0.000000, bitrate: 2957 kb/s
Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46),
yuv420p, 854x480 [SAR 1:1 DAR 427:240], 2500 kb/s, 24 fps, 24 tbr, 24 tbn,
24 tbc
Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side),
fltp, 448 kb/s
ffplay version 2.5.3 Copyright (c) 2003-2015 the FFmpeg developers
built on Feb 12 2015 19:55:48 with Apple LLVM version 6.0
(clang-600.0.56) (based on LLVM 3.5svn)
configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5.3 --enable-shared
--enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables
--enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-
libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid
--enable-libfontconfig --enable-libfreetype --enable-libtheora --enable-
libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libfaac --enable-libass --enable-
ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac
--enable-openssl --enable-libopus --enable-frei0r --enable-libcaca
--enable-libsoxr --enable-libquvi --enable-libvidstab --enable-libx265
--enable-libopenjpeg --disable-decoder=jpeg2000 --extra-
cflags='-I/usr/local/Cellar/openjpeg/1.5.1_1/include/openjpeg-1.5 '
--enable-nonfree --enable-vda
Input #1, png_pipe, from 'logo.png':
Duration: N/A, bitrate: N/A
Stream #1:0: Video: png, rgb24, 400x300 [SAR 11811:11811 DAR 4:3],
libavutil 54. 15.100 / 54. 15.100
25 fps, libavcodec 56. 13.100 / 56. 13.100
25 tbr, 25 tbn, libavformat 56. 15.102 / 56. 15.102
25 tbc
libavdevice 56. 3.100 / 56. 3.100
libavfilter 5. 2.103 / 5. 2.103
libavresample 2. 1. 0 / 2. 1. 0
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
[libx264 @ 0x7fa83d009200] using SAR=1/1
[libx264 @ 0x7fa83d009200] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX
[libx264 @ 0x7fa83d009200] profile High, level 3.0
[libx264 @ 0x7fa83d009200] 264 - core 142 r2495 6a301b6 - H.264/MPEG-4 AVC
codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options:
cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1
psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1
cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12
lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0
bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24
scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'pipe:': 0KB vq= 0KB sq= 0B f=0/0
Metadata:
encoder : Lavf56.15.102
Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv420p,
854x480 [SAR 1:1 DAR 427:240], q=-1--1, 24 fps, 1k tbn, 24 tbc (default)
Metadata:
encoder : Lavc56.13.100 libx264
Stream #0:1: Audio: vorbis (libvorbis) (oV[0][0] / 0x566F), 48000 Hz,
5.1(side), fltp
Metadata:
encoder : Lavc56.13.100 libvorbis
Stream mapping:
Stream #0:0 (mpeg4) -> overlay:main (graph 0)
Stream #1:0 (png) -> fade (graph 0)
overlay (graph 0) -> Stream #0:0 (libx264)
Stream #0:1 -> #0:1 (ac3 (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
}}}
[[Image(http://i.stack.imgur.com/Xlrm3.png)]]
The only workaround to have the image fade in from transparent (which is
what everyone would usually like to do) is to add the
`format=pix_fmts=yuva420p` filter before the fade in.
As this filter also works when the original image contains an alpha
channel, wouldn't it make sense to change the `fade` filter in such a way
that it automatically fades from transparent when its `alpha` option is
enabled? The defaulting to black does not make sense when the user wants
alpha channel fading (i.e. "transparency fading").
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4321>
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