/* * RTP VP8 Depacketizer * Copyright (c) 2010 Josh Allmann * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * @brief RTP support for the VP8 payload * @author Josh Allmann <joshua.allmann@gmail.com> * ( http://www.webmproject.org/code/specs/rtp/ ) */ #include "libavcodec/bytestream.h" #include "rtpdec_formats.h" struct PayloadContext { AVIOContext *data; uint32_t timestamp; int is_keyframe; }; static void prepare_packet(AVPacket *pkt, PayloadContext *vp8, int stream) { av_init_packet(pkt); pkt->stream_index = stream; pkt->flags = vp8->is_keyframe ? AV_PKT_FLAG_KEY : 0; pkt->size = avio_close_dyn_buf(vp8->data, &pkt->data); pkt->destruct = av_destruct_packet; vp8->data = NULL; } static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, int flags) { int start_packet, end_packet, has_au, ret = AVERROR(EAGAIN); if (!buf) { // only called when vp8_handle_packet returns 1 if (!vp8->data) { av_log(ctx, AV_LOG_ERROR, "Invalid VP8 data passed\n"); return AVERROR_INVALIDDATA; } prepare_packet(pkt, vp8, st->index); *timestamp = vp8->timestamp; return 0; } start_packet = *buf & 1; end_packet = flags & RTP_FLAG_MARKER; has_au = *buf & 2; buf++; len--; if (start_packet) { int res; uint32_t ts = *timestamp; if (vp8->data) { // missing end marker; return old frame anyway. untested prepare_packet(pkt, vp8, st->index); *timestamp = vp8->timestamp; // reset timestamp from old frame // if current frame fits into one rtp packet, need to hold // that for the next av_get_packet call ret = end_packet ? 1 : 0; } if ((res = avio_open_dyn_buf(&vp8->data)) < 0) return res; vp8->is_keyframe = *buf & 1; vp8->timestamp = ts; } if (!vp8->data || vp8->timestamp != *timestamp && ret == AVERROR(EAGAIN)) { av_log(ctx, AV_LOG_WARNING, "Received no start marker; dropping frame\n"); return AVERROR(EAGAIN); } // cycle through VP8AU headers if needed // not tested with actual VP8AUs while (len) { int au_len = len; if (has_au && len > 2) { au_len = AV_RB16(buf); buf += 2; len -= 2; if (buf + au_len > buf + len) { av_log(ctx, AV_LOG_ERROR, "Invalid VP8AU length\n"); return AVERROR_INVALIDDATA; } } avio_write(vp8->data, buf, au_len); buf += au_len; len -= au_len; } if (ret != AVERROR(EAGAIN)) // did we miss a end marker? return ret; if (end_packet) { prepare_packet(pkt, vp8, st->index); return 0; } return AVERROR(EAGAIN); } static PayloadContext *vp8_new_context(void) { av_log(NULL, AV_LOG_ERROR, "RTP VP8 payload implementation is incompatible " "with the latest spec drafts.\n"); return av_mallocz(sizeof(PayloadContext)); } static void vp8_free_context(PayloadContext *vp8) { if (vp8->data) { uint8_t *tmp; avio_close_dyn_buf(vp8->data, &tmp); av_free(tmp); } av_free(vp8); } RTPDynamicProtocolHandler ff_vp8_dynamic_handler = { .enc_name = "VP8", .codec_type = AVMEDIA_TYPE_VIDEO, .codec_id = CODEC_ID_VP8, .alloc = vp8_new_context, .free = vp8_free_context, .parse_packet = vp8_handle_packet, };