diff options
author | Urvang Joshi <urvang@google.com> | 2015-05-20 03:39:54 +0300 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2015-05-22 01:17:53 +0300 |
commit | 6b56fcbd10a56d2a7a116c0de4ee032b895456c2 (patch) | |
tree | a2f5b6ef7ba47e1e95eaa88b1afd0b054cec78f2 /libavformat | |
parent | 1c6ede3360c49daa64e0089d9b2f3e456545760c (diff) |
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.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavformat')
-rw-r--r-- | libavformat/webpenc.c | 79 |
1 files changed, 64 insertions, 15 deletions
diff --git a/libavformat/webpenc.c b/libavformat/webpenc.c index ee110de2dd..69270c63c4 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 +48,29 @@ 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 (pkt->size < 4) + return 0; + if (AV_RL32(pkt->data) == AV_RL32("RIFF")) + skip = 12; + + if (pkt->size < skip + 4) + return 0; + 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; } @@ -61,15 +84,25 @@ static int flush(AVFormatContext *s, int trailer, int64_t pts) unsigned flags = 0; int vp8x = 0; + if (w->last_pkt.size < 4) + return 0; if (AV_RL32(w->last_pkt.data) == AV_RL32("RIFF")) skip = 12; + + if (w->last_pkt.size < skip + 4) + return 0; // Safe to do this as a valid WebP bitstream is >=30 bytes. if (AV_RL32(w->last_pkt.data + skip) == AV_RL32("VP8X")) { flags |= w->last_pkt.data[skip + 4 + 4]; vp8x = 1; 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 +149,18 @@ 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 +168,24 @@ 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; } |