| /* |
| * Animated GIF muxer |
| * Copyright (c) 2000 Fabrice Bellard |
| * |
| * first version by Francois Revol <revol@free.fr> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "avformat.h" |
| #include "internal.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/imgutils.h" |
| #include "libavutil/log.h" |
| #include "libavutil/opt.h" |
| #include "libavcodec/bytestream.h" |
| #include "libavcodec/gif.h" |
| |
| typedef struct GIFContext { |
| AVClass *class; |
| int loop; |
| int last_delay; |
| int duration; |
| int64_t last_pos; |
| int have_end; |
| AVPacket *prev_pkt; |
| } GIFContext; |
| |
| static int gif_write_header(AVFormatContext *s) |
| { |
| if (s->nb_streams != 1 || |
| s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO || |
| s->streams[0]->codecpar->codec_id != AV_CODEC_ID_GIF) { |
| av_log(s, AV_LOG_ERROR, |
| "GIF muxer supports only a single video GIF stream.\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| avpriv_set_pts_info(s->streams[0], 64, 1, 100); |
| |
| return 0; |
| } |
| |
| static int gif_parse_packet(AVFormatContext *s, uint8_t *data, int size) |
| { |
| GetByteContext gb; |
| int x; |
| |
| bytestream2_init(&gb, data, size); |
| |
| while (bytestream2_get_bytes_left(&gb) > 0) { |
| x = bytestream2_get_byte(&gb); |
| if (x != GIF_EXTENSION_INTRODUCER) |
| return 0; |
| |
| x = bytestream2_get_byte(&gb); |
| while (x != GIF_GCE_EXT_LABEL && bytestream2_get_bytes_left(&gb) > 0) { |
| int block_size = bytestream2_get_byte(&gb); |
| if (!block_size) |
| break; |
| bytestream2_skip(&gb, block_size); |
| } |
| |
| if (x == GIF_GCE_EXT_LABEL) |
| return bytestream2_tell(&gb) + 2; |
| } |
| |
| return 0; |
| } |
| |
| static int gif_get_delay(GIFContext *gif, AVPacket *prev, AVPacket *new) |
| { |
| if (new && new->pts != AV_NOPTS_VALUE) |
| gif->duration = av_clip_uint16(new->pts - prev->pts); |
| else if (!new && gif->last_delay >= 0) |
| gif->duration = gif->last_delay; |
| |
| return gif->duration; |
| } |
| |
| static int gif_write_packet(AVFormatContext *s, AVPacket *new_pkt) |
| { |
| GIFContext *gif = s->priv_data; |
| AVIOContext *pb = s->pb; |
| AVPacket *pkt = gif->prev_pkt; |
| |
| if (!gif->prev_pkt) { |
| gif->prev_pkt = av_packet_alloc(); |
| if (!gif->prev_pkt) |
| return AVERROR(ENOMEM); |
| return av_packet_ref(gif->prev_pkt, new_pkt); |
| } |
| |
| gif->last_pos = avio_tell(pb); |
| if (pkt->size > 0) |
| gif->have_end = pkt->data[pkt->size - 1] == GIF_TRAILER; |
| |
| if (!gif->last_pos) { |
| int delay_pos; |
| int off = 13; |
| |
| if (pkt->size < 13) |
| return AVERROR(EINVAL); |
| |
| if (pkt->data[10] & 0x80) |
| off += 3 * (1 << ((pkt->data[10] & 0x07) + 1)); |
| |
| if (pkt->size < off + 2) |
| return AVERROR(EINVAL); |
| |
| avio_write(pb, pkt->data, off); |
| |
| if (pkt->data[off] == GIF_EXTENSION_INTRODUCER && pkt->data[off + 1] == 0xff) |
| off += 19; |
| |
| if (pkt->size <= off) |
| return AVERROR(EINVAL); |
| |
| /* "NETSCAPE EXTENSION" for looped animation GIF */ |
| if (gif->loop >= 0) { |
| avio_w8(pb, GIF_EXTENSION_INTRODUCER); /* GIF Extension code */ |
| avio_w8(pb, GIF_APP_EXT_LABEL); /* Application Extension Label */ |
| avio_w8(pb, 0x0b); /* Length of Application Block */ |
| avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1); |
| avio_w8(pb, 0x03); /* Length of Data Sub-Block */ |
| avio_w8(pb, 0x01); |
| avio_wl16(pb, (uint16_t)gif->loop); |
| avio_w8(pb, 0x00); /* Data Sub-block Terminator */ |
| } |
| |
| delay_pos = gif_parse_packet(s, pkt->data + off, pkt->size - off); |
| if (delay_pos > 0 && delay_pos < pkt->size - off - 2) { |
| avio_write(pb, pkt->data + off, delay_pos); |
| avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt)); |
| avio_write(pb, pkt->data + off + delay_pos + 2, pkt->size - off - delay_pos - 2); |
| } else { |
| avio_write(pb, pkt->data + off, pkt->size - off); |
| } |
| } else { |
| int delay_pos = gif_parse_packet(s, pkt->data, pkt->size); |
| |
| if (delay_pos > 0 && delay_pos < pkt->size - 2) { |
| avio_write(pb, pkt->data, delay_pos); |
| avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt)); |
| avio_write(pb, pkt->data + delay_pos + 2, pkt->size - delay_pos - 2); |
| } else { |
| avio_write(pb, pkt->data, pkt->size); |
| } |
| } |
| |
| av_packet_unref(gif->prev_pkt); |
| if (new_pkt) |
| return av_packet_ref(gif->prev_pkt, new_pkt); |
| |
| return 0; |
| } |
| |
| static int gif_write_trailer(AVFormatContext *s) |
| { |
| GIFContext *gif = s->priv_data; |
| AVIOContext *pb = s->pb; |
| |
| if (!gif->prev_pkt) |
| return AVERROR(EINVAL); |
| |
| gif_write_packet(s, NULL); |
| |
| if (!gif->have_end) |
| avio_w8(pb, GIF_TRAILER); |
| av_packet_free(&gif->prev_pkt); |
| |
| return 0; |
| } |
| |
| #define OFFSET(x) offsetof(GIFContext, x) |
| #define ENC AV_OPT_FLAG_ENCODING_PARAM |
| static const AVOption options[] = { |
| { "loop", "Number of times to loop the output: -1 - no loop, 0 - infinite loop", OFFSET(loop), |
| AV_OPT_TYPE_INT, { .i64 = 0 }, -1, 65535, ENC }, |
| { "final_delay", "Force delay (in centiseconds) after the last frame", OFFSET(last_delay), |
| AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 65535, ENC }, |
| { NULL }, |
| }; |
| |
| static const AVClass gif_muxer_class = { |
| .class_name = "GIF muxer", |
| .item_name = av_default_item_name, |
| .version = LIBAVUTIL_VERSION_INT, |
| .option = options, |
| }; |
| |
| AVOutputFormat ff_gif_muxer = { |
| .name = "gif", |
| .long_name = NULL_IF_CONFIG_SMALL("CompuServe Graphics Interchange Format (GIF)"), |
| .mime_type = "image/gif", |
| .extensions = "gif", |
| .priv_data_size = sizeof(GIFContext), |
| .audio_codec = AV_CODEC_ID_NONE, |
| .video_codec = AV_CODEC_ID_GIF, |
| .write_header = gif_write_header, |
| .write_packet = gif_write_packet, |
| .write_trailer = gif_write_trailer, |
| .priv_class = &gif_muxer_class, |
| .flags = AVFMT_VARIABLE_FPS, |
| }; |