From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 2E72643343 for ; Wed, 1 Jun 2022 17:52:28 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id B761968B791; Wed, 1 Jun 2022 20:52:27 +0300 (EEST) Received: from mail-yw1-f177.google.com (mail-yw1-f177.google.com [209.85.128.177]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 4AB2468B74F for ; Wed, 1 Jun 2022 20:52:22 +0300 (EEST) Received: by mail-yw1-f177.google.com with SMTP id 00721157ae682-2ff7b90e635so27118497b3.5 for ; Wed, 01 Jun 2022 10:52:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PKmvZiAXJnevgZaltmqgIK/ZroMzuMxfFD2m7UbfhCw=; b=YGCeKdXmrKHSqQsgR4r0K4LNfJtlwDs4UfXR5dmpw/MGsmBmr3beq2D/TE7GxyZNqX yJl5okodiq2yorcfi5HtaJ5R7C9yiqdOS65TylRt6axo/6Uht1Siuvf3rgsYJ1vBmT7Y 8eAAXCOIrTG9/lcRGvZiMeWtaBfToBxbfQBy2hundmVCx4A8Vq8RWids25V+04Vxw6oL QE5CEY3LwAedLZpADVxu0mKFs5FK0e+xHUZl/8cdCA39D47o3Vr9NFGT0S3CYYuUQKrd 0v0bf2pFhFglz9Hh2s7GMWPHG6K4zX0I+qFKm9fJQS4G+kFNwYpfZBoNldjrgip6pNfK dqAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PKmvZiAXJnevgZaltmqgIK/ZroMzuMxfFD2m7UbfhCw=; b=4vrsvZlC9fmBuzc9RLt671llc9IeSCbsBh6UBE4BOeAxZeXqqjfwk3p7sNnr5waiv/ EBbV/HYuWGnmMK1FcXRoNLFePHYlnEAFBVqBGN2tUQZHi/cu7F25vbU5plnbTE72nwoY q/1BFahfAR+eLLl01EDOX0lnbjc+zU94P/+sTMaZebatvCeFx+YHMNGAbg8w0zw9dl/y FcQZwMBJf7eWHQlMtTlhmtZGYdf7xKD75MczCjlsAQxnBBOdO9XK4g7WfCnqiUYFWPZ/ 7qG2PfaxLlVtlbjIr65CluyBJ0gHB2+yAReDOxUY3Fo09x+z/QOhTBd1uHs37nBmYItg BeBQ== X-Gm-Message-State: AOAM53002FTPveR2Y94SvEJcSiC1C5C/2bkHNxHzNZS9iUIWSIa9Fq/n cvPV+Zg0sfZivjNIY1EAjmdBP47uqObxiy4mG8/Oy0cQAf+VdQ== X-Google-Smtp-Source: ABdhPJzCdOqHO4retyKGYnyOSu/bBchhPPKv6fBEA+N+HDbWydBqbhDSLlBJASx4zK401jXWkZoGzoYPs/mASz58L/E= X-Received: by 2002:a05:690c:807:b0:30c:1e5f:7230 with SMTP id bx7-20020a05690c080700b0030c1e5f7230mr674972ywb.435.1654105940180; Wed, 01 Jun 2022 10:52:20 -0700 (PDT) MIME-Version: 1.0 References: <20220518215620.1718203-1-vigneshv@google.com> In-Reply-To: <20220518215620.1718203-1-vigneshv@google.com> From: James Zern Date: Wed, 1 Jun 2022 10:52:08 -0700 Message-ID: To: FFmpeg development discussions and patches Subject: Re: [FFmpeg-devel] [PATCH] avformat/movenc: Support alpha channel for AVIF X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: Vignesh Venkatasubramanian Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Wed, May 18, 2022 at 2:56 PM Vignesh Venkatasubramanian wrote: > > AVIF specification allows for alpha channel as an auxillary item (in auxiliary > case of still images) or as an auxillary track (in case of animated > images). Add support for both of these. The AVIF muxer will take > exactly two streams (when alpha is present) as input (first one being > the YUV planes and the second one being the alpha plane). > > The input has to come from two different images (one of it color and > the other one being alpha), or it can come from a single file > source with the alpha channel extracted using the "alphaextract" > filter. > > Example using alphaextract: > ffmpeg -i rgba.png -filter_complex "[0:v]alphaextract[a]" -map 0 -map "[a]" -still-picture 1 avif_with_alpha.avif > > Example using two sources (first source can be in any pixel format and > the second source has to be in monochrome grey pixel format): > ffmpeg -i color.avif -i grey.avif -map 0 -map 1 -c copy avif_with_alpha.avif > > The generated files pass the compliance checks in Compliance Warden: > https://github.com/gpac/ComplianceWarden > > libavif (the reference avif library) is able to decode the files > generated using this patch. > > They also play back properly (with transparent background) in: > 1) Chrome > 2) Firefox (only still AVIF, no animation support) > > Signed-off-by: Vignesh Venkatasubramanian > --- > libavformat/movenc.c | 185 +++++++++++++++++++++++++++++-------------- > libavformat/movenc.h | 4 +- > 2 files changed, 128 insertions(+), 61 deletions(-) > > diff --git a/libavformat/movenc.c b/libavformat/movenc.c > index de971f94e8..00e42b7abb 100644 > --- a/libavformat/movenc.c > +++ b/libavformat/movenc.c > @@ -2852,7 +2852,7 @@ static int mov_write_hdlr_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra > hdlr = (track->mode == MODE_MOV) ? "mhlr" : "\0\0\0\0"; > if (track->par->codec_type == AVMEDIA_TYPE_VIDEO) { > if (track->mode == MODE_AVIF) { > - hdlr_type = "pict"; > + hdlr_type = (track == &mov->tracks[0]) ? "pict" : "auxv"; > descr = "PictureHandler"; > } else { > hdlr_type = "vide"; > @@ -2940,57 +2940,83 @@ static int mov_write_iloc_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatConte > avio_wb32(pb, 0); /* Version & flags */ > avio_w8(pb, (4 << 4) + 4); /* offset_size(4) and length_size(4) */ > avio_w8(pb, 0); /* base_offset_size(4) and reserved(4) */ > - avio_wb16(pb, 1); /* item_count */ > + avio_wb16(pb, s->nb_streams); /* item_count */ This assumes at most 2 streams for AVIF, the use of nb_streams here and elsewhere carry any risk for other formats? > [...] > > @@ -6874,14 +6920,23 @@ static int mov_init(AVFormatContext *s) > > /* AVIF output must have exactly one video stream */ This is no longer true. > if (mov->mode == MODE_AVIF) { > - if (s->nb_streams > 1) { > - av_log(s, AV_LOG_ERROR, "AVIF output requires exactly one stream\n"); > + if (s->nb_streams > 2) { > + av_log(s, AV_LOG_ERROR, "AVIF output requires exactly one or two streams\n"); > return AVERROR(EINVAL); > } > - if (s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO) { > - av_log(s, AV_LOG_ERROR, "AVIF output requires one video stream\n"); > + if (s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO && > + (s->nb_streams > 1 && s->streams[1]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)) { > + av_log(s, AV_LOG_ERROR, "AVIF output supports only video streams\n"); > return AVERROR(EINVAL); > } > + if (s->nb_streams > 1) { > + const AVPixFmtDescriptor *pixdesc = > + av_pix_fmt_desc_get(s->streams[1]->codecpar->format); > + if (pixdesc->nb_components != 1) { > + av_log(s, AV_LOG_ERROR, "Second stream for AVIF (alpha) output must have exactly one plane\n"); > + return AVERROR(EINVAL); > + } > + } > s->streams[0]->disposition |= AV_DISPOSITION_DEFAULT; > } > > @@ -7543,18 +7598,25 @@ static int avif_write_trailer(AVFormatContext *s) > { > AVIOContext *pb = s->pb; > MOVMuxContext *mov = s->priv_data; > - int64_t pos_backup, mdat_pos; > + int64_t pos_backup, extent_offsets[2]; > uint8_t *buf; > - int buf_size, moov_size; > + int buf_size, moov_size, i; > > if (mov->moov_written) return 0; > > mov->is_animated_avif = s->streams[0]->nb_frames > 1; > + if (mov->is_animated_avif && s->nb_streams > 1) { > + // For animated avif with alpha channel, we need to write a the tref ...write a tref... _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".