On Wed, May 20, 2015 at 12:39 PM Michael Niedermayer <michae...@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 <urv...@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
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From ebca78a25a96bc172cc4de58f488b912ba20e220 Mon Sep 17 00:00:00 2001
From: Urvang Joshi <urv...@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];
+ }
+ if (flags & 2) // ANIMATION_FLAG is on
+ return 1;
+ }
return 0;
}
@@ -69,7 +87,12 @@ static int flush(AVFormatContext *s, int trailer, int64_t pts)
skip += AV_RL32(w->last_pkt.data + skip + 4) + 8;
}
- w->frame_count ++;
+ if (!w->wrote_webp_header) {
+ avio_write(s->pb, "RIFF\0\0\0\0WEBP", 12);
+ w->wrote_webp_header = 1;
+ if (w->frame_count > 1) // first non-empty packet
+ w->frame_count = 1; // so we don't count previous empty packets.
+ }
if (w->frame_count == 1) {
if (!trailer) {
@@ -116,12 +139,18 @@ static int flush(AVFormatContext *s, int trailer, int64_t pts)
static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
{
WebpContext *w = s->priv_data;
- int ret;
-
- if ((ret = flush(s, 0, pkt->pts)) < 0)
- return ret;
-
- av_copy_packet(&w->last_pkt, pkt);
+ w->using_webp_anim_encoder |= is_animated_webp_packet(pkt);
+
+ if (w->using_webp_anim_encoder) {
+ avio_write(s->pb, pkt->data, pkt->size);
+ w->wrote_webp_header = 1; // for good measure
+ } else {
+ int ret;
+ if ((ret = flush(s, 0, pkt->pts)) < 0)
+ return ret;
+ av_copy_packet(&w->last_pkt, pkt);
+ }
+ ++w->frame_count;
return 0;
}
@@ -129,14 +158,24 @@ static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
static int webp_write_trailer(AVFormatContext *s)
{
unsigned filesize;
- int ret;
-
- if ((ret = flush(s, 1, AV_NOPTS_VALUE)) < 0)
- return ret;
+ WebpContext *w = s->priv_data;
- filesize = avio_tell(s->pb);
- avio_seek(s->pb, 4, SEEK_SET);
- avio_wl32(s->pb, filesize - 8);
+ if (w->using_webp_anim_encoder) {
+ if ((w->frame_count > 1) && w->loop) { // Write loop count.
+ avio_seek(s->pb, 42, SEEK_SET);
+ avio_wl16(s->pb, w->loop);
+ }
+ } else {
+ int ret;
+ if ((ret = flush(s, 1, AV_NOPTS_VALUE)) < 0)
+ return ret;
+
+ filesize = avio_tell(s->pb);
+ avio_seek(s->pb, 4, SEEK_SET);
+ avio_wl32(s->pb, filesize - 8);
+ // Note: without the following, avio only writes 8 bytes to the file.
+ avio_seek(s->pb, filesize, SEEK_SET);
+ }
return 0;
}
--
2.2.0.rc0.207.ga3a616c
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