[FFmpeg-devel] WebP muxer: support packet containing animated WebP

[Michael Niedermayer]

On Wed, May 20, 2015 at 11:52:17PM +0000, Urvang Joshi wrote:
> On Wed, May 20, 2015 at 12:39 PM Michael Niedermayer <michaelni at gmx.at>
> wrote:
> 
> > On Wed, May 20, 2015 at 01:56:17AM +0000, Urvang Joshi wrote:
> > > This is 1st out of 3 patches.
> > > Attached.
> >
> > >  webpenc.c |   63
> > +++++++++++++++++++++++++++++++++++++++++++++-----------------
> > >  1 file changed, 46 insertions(+), 17 deletions(-)
> > > ee0eae792572bbcce5b6ce0e982e1347f0241418
> > 1.WebP-muxer-support-a-packet-containing-animated-WebP.patch
> > > From a47778d6b0514097668881c9d2f5ecbfce5970a3 Mon Sep 17 00:00:00 2001
> > > From: Urvang Joshi <urvang at google.com>
> > > Date: Tue, 19 May 2015 17:39:54 -0700
> > > Subject: [PATCH] WebP muxer: support a packet containing animated WebP.
> > >
> > > This is the 1st patch in preparation for using WebPAnimEncoder API for
> > encoding
> > > and muxing WebP images.
> >
> > this breaks the code
> >
> >
> > ./ffmpeg -i lena.pnm  test.webp
> > vwebp test.webp
> > "Input file doesn't appear to be WebP format."
> >
> 
> Thanks for catching! Here's an updated patch which works for static images
> too.
> 
> 
> 
> 
> >
> > [...]
> >
> > --
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > In a rich man's house there is no place to spit but his face.
> > -- Diogenes of Sinope
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >

>  webpenc.c |   69 ++++++++++++++++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 54 insertions(+), 15 deletions(-)
> e288e8a4e46c4837a37b1191a64f709391e634f2  1.WebP-muxer-support-a-packet-containing-animated-WebP.patch
> From ebca78a25a96bc172cc4de58f488b912ba20e220 Mon Sep 17 00:00:00 2001
> From: Urvang Joshi <urvang at google.com>
> Date: Tue, 19 May 2015 17:39:54 -0700
> Subject: [PATCH] WebP muxer: support a packet containing animated WebP.
> 
> This is the 1st patch in preparation for using WebPAnimEncoder API for encoding
> and muxing WebP images.
> ---
>  libavformat/webpenc.c | 69 ++++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 54 insertions(+), 15 deletions(-)
> 
> diff --git a/libavformat/webpenc.c b/libavformat/webpenc.c
> index ee110de..8a5a5ce 100644
> --- a/libavformat/webpenc.c
> +++ b/libavformat/webpenc.c
> @@ -29,6 +29,8 @@ typedef struct WebpContext{
>      int frame_count;
>      AVPacket last_pkt;
>      int loop;
> +    int wrote_webp_header;
> +    int using_webp_anim_encoder;
>  } WebpContext;
>  
>  static int webp_write_header(AVFormatContext *s)
> @@ -46,8 +48,24 @@ static int webp_write_header(AVFormatContext *s)
>      }
>      avpriv_set_pts_info(st, 24, 1, 1000);
>  
> -    avio_write(s->pb, "RIFF\0\0\0\0WEBP", 12);
> +    return 0;
> +}
> +
> +static int is_animated_webp_packet(AVPacket *pkt)
> +{
> +    if (pkt->size) {
> +        int skip = 0;
> +        unsigned flags = 0;
> +
> +        if (AV_RL32(pkt->data) == AV_RL32("RIFF"))
> +            skip = 12;
> +        if (AV_RL32(pkt->data + skip) == AV_RL32("VP8X")) {
> +            flags |= pkt->data[skip + 4 + 4];
> +        }

the array size should be checked before reading from the array

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
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