| /* |
| * RTP VP8 Depacketizer |
| * Copyright (c) 2010 Josh Allmann |
| * Copyright (c) 2012 Martin Storsjo |
| * |
| * 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> |
| * @see http://tools.ietf.org/html/draft-ietf-payload-vp8-05 |
| */ |
| |
| #include "libavcodec/bytestream.h" |
| |
| #include "avio_internal.h" |
| #include "rtpdec_formats.h" |
| |
| struct PayloadContext { |
| AVIOContext *data; |
| uint32_t timestamp; |
| int is_keyframe; |
| /* If sequence_ok is set, we keep returning data (even if we might have |
| * lost some data, but we haven't lost any too critical data that would |
| * cause the decoder to desynchronize and output random garbage). |
| */ |
| int sequence_ok; |
| int first_part_size; |
| uint16_t prev_seq; |
| int prev_pictureid; |
| int broken_frame; |
| /* If sequence_dirty is set, we have lost some data (critical or |
| * non-critical) and decoding will have some sort of artefacts, and |
| * we thus should request a new keyframe. |
| */ |
| int sequence_dirty; |
| int got_keyframe; |
| }; |
| |
| static int vp8_broken_sequence(AVFormatContext *ctx, PayloadContext *vp8, |
| const char *msg) |
| { |
| vp8->sequence_ok = 0; |
| av_log(ctx, AV_LOG_WARNING, "%s", msg); |
| ffio_free_dyn_buf(&vp8->data); |
| return AVERROR(EAGAIN); |
| } |
| |
| static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8, |
| AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
| const uint8_t *buf, int len, uint16_t seq, |
| int flags) |
| { |
| int start_partition, end_packet; |
| int extended_bits, part_id; |
| int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0, |
| keyidx_present = 0; |
| int pictureid = -1, pictureid_mask = 0; |
| int returned_old_frame = 0; |
| uint32_t old_timestamp = 0; |
| |
| if (!buf) { |
| if (vp8->data) { |
| int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); |
| if (ret < 0) |
| return ret; |
| *timestamp = vp8->timestamp; |
| if (vp8->sequence_dirty) |
| pkt->flags |= AV_PKT_FLAG_CORRUPT; |
| return 0; |
| } |
| return AVERROR(EAGAIN); |
| } |
| |
| if (len < 1) |
| return AVERROR_INVALIDDATA; |
| |
| extended_bits = buf[0] & 0x80; |
| start_partition = buf[0] & 0x10; |
| part_id = buf[0] & 0x0f; |
| end_packet = flags & RTP_FLAG_MARKER; |
| buf++; |
| len--; |
| if (extended_bits) { |
| if (len < 1) |
| return AVERROR_INVALIDDATA; |
| pictureid_present = buf[0] & 0x80; |
| tl0picidx_present = buf[0] & 0x40; |
| tid_present = buf[0] & 0x20; |
| keyidx_present = buf[0] & 0x10; |
| buf++; |
| len--; |
| } |
| if (pictureid_present) { |
| if (len < 1) |
| return AVERROR_INVALIDDATA; |
| if (buf[0] & 0x80) { |
| if (len < 2) |
| return AVERROR_INVALIDDATA; |
| pictureid = AV_RB16(buf) & 0x7fff; |
| pictureid_mask = 0x7fff; |
| buf += 2; |
| len -= 2; |
| } else { |
| pictureid = buf[0] & 0x7f; |
| pictureid_mask = 0x7f; |
| buf++; |
| len--; |
| } |
| } |
| if (tl0picidx_present) { |
| // Ignoring temporal level zero index |
| buf++; |
| len--; |
| } |
| if (tid_present || keyidx_present) { |
| // Ignoring temporal layer index, layer sync bit and keyframe index |
| buf++; |
| len--; |
| } |
| if (len < 1) |
| return AVERROR_INVALIDDATA; |
| |
| if (start_partition && part_id == 0 && len >= 3) { |
| int res; |
| int non_key = buf[0] & 0x01; |
| if (!non_key) { |
| ffio_free_dyn_buf(&vp8->data); |
| // Keyframe, decoding ok again |
| vp8->sequence_ok = 1; |
| vp8->sequence_dirty = 0; |
| vp8->got_keyframe = 1; |
| } else { |
| int can_continue = vp8->data && !vp8->is_keyframe && |
| avio_tell(vp8->data) >= vp8->first_part_size; |
| if (!vp8->sequence_ok) |
| return AVERROR(EAGAIN); |
| if (!vp8->got_keyframe) |
| return vp8_broken_sequence(ctx, vp8, "Keyframe missing\n"); |
| if (pictureid >= 0) { |
| if (pictureid != ((vp8->prev_pictureid + 1) & pictureid_mask)) { |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed a picture, sequence broken\n"); |
| } else { |
| if (vp8->data && !can_continue) |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed a picture, sequence broken\n"); |
| } |
| } else { |
| uint16_t expected_seq = vp8->prev_seq + 1; |
| int16_t diff = seq - expected_seq; |
| if (vp8->data) { |
| // No picture id, so we can't know if missed packets |
| // contained any new frames. If diff == 0, we did get |
| // later packets from the same frame (matching timestamp), |
| // so we know we didn't miss any frame. If diff == 1 and |
| // we still have data (not flushed by the end of frame |
| // marker), the single missed packet must have been part |
| // of the same frame. |
| if ((diff == 0 || diff == 1) && can_continue) { |
| // Proceed with what we have |
| } else { |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed too much, sequence broken\n"); |
| } |
| } else { |
| if (diff != 0) |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed unknown data, sequence broken\n"); |
| } |
| } |
| if (vp8->data) { |
| vp8->sequence_dirty = 1; |
| if (avio_tell(vp8->data) >= vp8->first_part_size) { |
| int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); |
| if (ret < 0) |
| return ret; |
| pkt->flags |= AV_PKT_FLAG_CORRUPT; |
| returned_old_frame = 1; |
| old_timestamp = vp8->timestamp; |
| } else { |
| // Shouldn't happen |
| ffio_free_dyn_buf(&vp8->data); |
| } |
| } |
| } |
| vp8->first_part_size = (AV_RL16(&buf[1]) << 3 | buf[0] >> 5) + 3; |
| if ((res = avio_open_dyn_buf(&vp8->data)) < 0) |
| return res; |
| vp8->timestamp = *timestamp; |
| vp8->broken_frame = 0; |
| vp8->prev_pictureid = pictureid; |
| vp8->is_keyframe = !non_key; |
| } else { |
| uint16_t expected_seq = vp8->prev_seq + 1; |
| |
| if (!vp8->sequence_ok) |
| return AVERROR(EAGAIN); |
| |
| if (vp8->timestamp != *timestamp) { |
| // Missed the start of the new frame, sequence broken |
| return vp8_broken_sequence(ctx, vp8, |
| "Received no start marker; dropping frame\n"); |
| } |
| |
| if (seq != expected_seq) { |
| if (vp8->is_keyframe) { |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed part of a keyframe, sequence broken\n"); |
| } else if (vp8->data && avio_tell(vp8->data) >= vp8->first_part_size) { |
| vp8->broken_frame = 1; |
| vp8->sequence_dirty = 1; |
| } else { |
| return vp8_broken_sequence(ctx, vp8, |
| "Missed part of the first partition, sequence broken\n"); |
| } |
| } |
| } |
| |
| if (!vp8->data) |
| return vp8_broken_sequence(ctx, vp8, "Received no start marker\n"); |
| |
| vp8->prev_seq = seq; |
| if (!vp8->broken_frame) |
| avio_write(vp8->data, buf, len); |
| |
| if (returned_old_frame) { |
| *timestamp = old_timestamp; |
| return end_packet ? 1 : 0; |
| } |
| |
| if (end_packet) { |
| int ret; |
| ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); |
| if (ret < 0) |
| return ret; |
| if (vp8->sequence_dirty) |
| pkt->flags |= AV_PKT_FLAG_CORRUPT; |
| if (vp8->is_keyframe) |
| pkt->flags |= AV_PKT_FLAG_KEY; |
| return 0; |
| } |
| |
| return AVERROR(EAGAIN); |
| } |
| |
| static av_cold int vp8_init(AVFormatContext *s, int st_index, PayloadContext *vp8) |
| { |
| vp8->sequence_ok = 1; |
| return 0; |
| } |
| |
| static void vp8_close_context(PayloadContext *vp8) |
| { |
| ffio_free_dyn_buf(&vp8->data); |
| } |
| |
| static int vp8_need_keyframe(PayloadContext *vp8) |
| { |
| return vp8->sequence_dirty || !vp8->sequence_ok; |
| } |
| |
| RTPDynamicProtocolHandler ff_vp8_dynamic_handler = { |
| .enc_name = "VP8", |
| .codec_type = AVMEDIA_TYPE_VIDEO, |
| .codec_id = AV_CODEC_ID_VP8, |
| .priv_data_size = sizeof(PayloadContext), |
| .init = vp8_init, |
| .close = vp8_close_context, |
| .parse_packet = vp8_handle_packet, |
| .need_keyframe = vp8_need_keyframe, |
| }; |
