diff options
author | Clément Bœsch <u@pkh.me> | 2015-01-23 16:34:14 +0100 |
---|---|---|
committer | Clément Bœsch <u@pkh.me> | 2015-02-14 20:48:50 +0100 |
commit | 5f9986f597e8a60d05b2f3fb63de5a423b82f9e3 (patch) | |
tree | 92d937d10a1cc263933e0d94ede9601f90277fa1 | |
parent | adb9b235b6eb61d0dccf733f8bb03894659318d4 (diff) | |
download | ffmpeg-5f9986f597e8a60d05b2f3fb63de5a423b82f9e3.tar.gz |
avformat/gif: use first packet palette as global for PAL8
This will allow the payload in PAL8 packets to not contain 768B of local
palette (which is not LZW compressed).
-rw-r--r-- | libavformat/gif.c | 70 |
1 files changed, 50 insertions, 20 deletions
diff --git a/libavformat/gif.c b/libavformat/gif.c index b4c5e8b8c4..a729cc70b3 100644 --- a/libavformat/gif.c +++ b/libavformat/gif.c @@ -28,6 +28,28 @@ #include "libavutil/log.h" #include "libavutil/opt.h" +/* XXX: random value that shouldn't be taken into effect if there is no + * transparent color in the palette (the transparency bit will be set to 0) */ +#define DEFAULT_TRANSPARENCY_INDEX 0x1f + +static int get_palette_transparency_index(const uint32_t *palette) +{ + int transparent_color_index = -1; + unsigned i, smallest_alpha = 0xff; + + if (!palette) + return -1; + + for (i = 0; i < AVPALETTE_COUNT; i++) { + const uint32_t v = palette[i]; + if (v >> 24 < smallest_alpha) { + smallest_alpha = v >> 24; + transparent_color_index = i; + } + } + return smallest_alpha < 128 ? transparent_color_index : -1; +} + static int gif_image_write_header(AVIOContext *pb, const AVCodecContext *avctx, int loop_count, uint32_t *palette) { @@ -47,8 +69,10 @@ static int gif_image_write_header(AVIOContext *pb, const AVCodecContext *avctx, avio_wl16(pb, avctx->height); if (palette) { + const int bcid = get_palette_transparency_index(palette); + avio_w8(pb, 0xf7); /* flags: global clut, 256 entries */ - avio_w8(pb, 0x1f); /* background color index */ + avio_w8(pb, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); /* background color index */ avio_w8(pb, aspect); for (i = 0; i < 256; i++) { const uint32_t v = palette[i] & 0xffffff; @@ -73,6 +97,7 @@ static int gif_image_write_header(AVIOContext *pb, const AVCodecContext *avctx, avio_w8(pb, 0x00); /* Data Sub-block Terminator */ } + avio_flush(pb); return 0; } @@ -103,21 +128,20 @@ static int gif_write_header(AVFormatContext *s) avpriv_set_pts_info(s->streams[0], 64, 1, 100); if (avpriv_set_systematic_pal2(palette, video_enc->pix_fmt) < 0) { av_assert0(video_enc->pix_fmt == AV_PIX_FMT_PAL8); - gif_image_write_header(s->pb, video_enc, gif->loop, NULL); + /* delay header writing: we wait for the first palette to put it + * globally */ } else { gif_image_write_header(s->pb, video_enc, gif->loop, palette); } - avio_flush(s->pb); return 0; } static int flush_packet(AVFormatContext *s, AVPacket *new) { GIFContext *gif = s->priv_data; - int size; + int size, bcid; AVIOContext *pb = s->pb; - uint8_t flags = 0x4, transparent_color_index = 0x1f; const uint32_t *palette; AVPacket *pkt = gif->prev_pkt; @@ -131,19 +155,7 @@ static int flush_packet(AVFormatContext *s, AVPacket *new) av_log(s, AV_LOG_ERROR, "Invalid palette extradata\n"); return AVERROR_INVALIDDATA; } - if (palette) { - unsigned i, smallest_alpha = 0xff; - - for (i = 0; i < AVPALETTE_COUNT; i++) { - const uint32_t v = palette[i]; - if (v >> 24 < smallest_alpha) { - smallest_alpha = v >> 24; - transparent_color_index = i; - } - } - if (smallest_alpha < 128) - flags |= 0x1; /* Transparent Color Flag */ - } + bcid = get_palette_transparency_index(palette); if (new && new->pts != AV_NOPTS_VALUE) gif->duration = av_clip_uint16(new->pts - gif->prev_pkt->pts); @@ -154,9 +166,9 @@ static int flush_packet(AVFormatContext *s, AVPacket *new) avio_w8(pb, 0x21); avio_w8(pb, 0xf9); avio_w8(pb, 0x04); /* block size */ - avio_w8(pb, flags); + avio_w8(pb, 1<<2 | (bcid >= 0)); avio_wl16(pb, gif->duration); - avio_w8(pb, transparent_color_index); + avio_w8(pb, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); avio_w8(pb, 0x00); avio_write(pb, pkt->data, pkt->size); @@ -171,11 +183,29 @@ static int flush_packet(AVFormatContext *s, AVPacket *new) static int gif_write_packet(AVFormatContext *s, AVPacket *pkt) { GIFContext *gif = s->priv_data; + const AVCodecContext *video_enc = s->streams[0]->codec; if (!gif->prev_pkt) { gif->prev_pkt = av_malloc(sizeof(*gif->prev_pkt)); if (!gif->prev_pkt) return AVERROR(ENOMEM); + + /* Write the first palette as global palette */ + if (video_enc->pix_fmt == AV_PIX_FMT_PAL8) { + int size; + void *palette = av_packet_get_side_data(pkt, AV_PKT_DATA_PALETTE, &size); + + if (!palette) { + av_log(s, AV_LOG_ERROR, "PAL8 packet is missing palette in extradata\n"); + return AVERROR_INVALIDDATA; + } + if (size != AVPALETTE_SIZE) { + av_log(s, AV_LOG_ERROR, "Invalid palette extradata\n"); + return AVERROR_INVALIDDATA; + } + gif_image_write_header(s->pb, video_enc, gif->loop, palette); + } + return av_copy_packet(gif->prev_pkt, pkt); } return flush_packet(s, pkt); |