| /* |
| * RTP VP8 Depacketizer |
| * Copyright (c) 2010 Josh Allmann |
| * |
| * 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 |
| */ |
| |
| /** |
| * @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, |
| }; |