| /* |
| * RTP parser for VP9 payload format (draft version 0) - experimental |
| * Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com> |
| * |
| * 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 "libavutil/intreadwrite.h" |
| |
| #include "avio_internal.h" |
| #include "rtpdec_formats.h" |
| |
| #define RTP_VP9_DESC_REQUIRED_SIZE 1 |
| |
| struct PayloadContext { |
| AVIOContext *buf; |
| uint32_t timestamp; |
| }; |
| |
| static av_cold int vp9_init(AVFormatContext *ctx, int st_index, |
| PayloadContext *data) |
| { |
| av_log(ctx, AV_LOG_WARNING, |
| "RTP/VP9 support is still experimental\n"); |
| |
| return 0; |
| } |
| |
| static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx, |
| AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
| const uint8_t *buf, int len, uint16_t seq, |
| int flags) |
| { |
| int has_pic_id, has_layer_idc, has_ref_idc, has_ss_data, has_su_data; |
| av_unused int pic_id = 0, non_key_frame = 0; |
| av_unused int layer_temporal = -1, layer_spatial = -1, layer_quality = -1; |
| int ref_fields = 0, has_ref_field_ext_pic_id = 0; |
| int first_fragment, last_fragment; |
| int rtp_m; |
| int res = 0; |
| |
| /* drop data of previous packets in case of non-continuous (lossy) packet stream */ |
| if (rtp_vp9_ctx->buf && rtp_vp9_ctx->timestamp != *timestamp) |
| ffio_free_dyn_buf(&rtp_vp9_ctx->buf); |
| |
| /* sanity check for size of input packet: 1 byte payload at least */ |
| if (len < RTP_VP9_DESC_REQUIRED_SIZE + 1) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet, got %d bytes\n", len); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* |
| * decode the required VP9 payload descriptor according to section 4.2 of the spec.: |
| * |
| * 0 1 2 3 4 5 6 7 |
| * +-+-+-+-+-+-+-+-+ |
| * |I|L|F|B|E|V|U|-| (REQUIRED) |
| * +-+-+-+-+-+-+-+-+ |
| * |
| * I: PictureID present |
| * L: Layer indices present |
| * F: Reference indices present |
| * B: Start of VP9 frame |
| * E: End of picture |
| * V: Scalability Structure (SS) present |
| * U: Scalability Structure Update (SU) present |
| */ |
| has_pic_id = !!(buf[0] & 0x80); |
| has_layer_idc = !!(buf[0] & 0x40); |
| has_ref_idc = !!(buf[0] & 0x20); |
| first_fragment = !!(buf[0] & 0x10); |
| last_fragment = !!(buf[0] & 0x08); |
| has_ss_data = !!(buf[0] & 0x04); |
| has_su_data = !!(buf[0] & 0x02); |
| |
| rtp_m = !!(flags & RTP_FLAG_MARKER); |
| |
| /* sanity check for markers: B should always be equal to the RTP M marker */ |
| if (last_fragment != rtp_m) { |
| av_log(ctx, AV_LOG_ERROR, "Invalid combination of B and M marker (%d != %d)\n", last_fragment, rtp_m); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* pass the extensions field */ |
| buf += RTP_VP9_DESC_REQUIRED_SIZE; |
| len -= RTP_VP9_DESC_REQUIRED_SIZE; |
| |
| /* |
| * decode the 1-byte/2-byte picture ID: |
| * |
| * 0 1 2 3 4 5 6 7 |
| * +-+-+-+-+-+-+-+-+ |
| * I: |M|PICTURE ID | (RECOMMENDED) |
| * +-+-+-+-+-+-+-+-+ |
| * M: | EXTENDED PID | (RECOMMENDED) |
| * +-+-+-+-+-+-+-+-+ |
| * |
| * M: The most significant bit of the first octet is an extension flag. |
| * PictureID: 8 or 16 bits including the M bit. |
| */ |
| if (has_pic_id) { |
| /* check for 1-byte or 2-byte picture index */ |
| if (buf[0] & 0x80) { |
| if (len < 2) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| pic_id = AV_RB16(buf) & 0x7fff; |
| buf += 2; |
| len -= 2; |
| } else { |
| pic_id = buf[0] & 0x7f; |
| buf++; |
| len--; |
| } |
| } |
| |
| /* |
| * decode layer indices |
| * |
| * 0 1 2 3 4 5 6 7 |
| * +-+-+-+-+-+-+-+-+ |
| * L: | T | S | Q | R | (CONDITIONALLY RECOMMENDED) |
| * +-+-+-+-+-+-+-+-+ |
| * |
| * T, S and Q are 2-bit indices for temporal, spatial, and quality layers. |
| * If "F" is set in the initial octet, R is 2 bits representing the number |
| * of reference fields this frame refers to. |
| */ |
| if (has_layer_idc) { |
| if (len < 1) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| layer_temporal = buf[0] & 0xC0; |
| layer_spatial = buf[0] & 0x30; |
| layer_quality = buf[0] & 0x0C; |
| if (has_ref_idc) { |
| ref_fields = buf[0] & 0x03; |
| if (ref_fields) |
| non_key_frame = 1; |
| } |
| buf++; |
| len--; |
| } |
| |
| /* |
| * decode the reference fields |
| * |
| * 0 1 2 3 4 5 6 7 |
| * +-+-+-+-+-+-+-+-+ -\ |
| * F: | PID |X| RS| RQ| (OPTIONAL) . |
| * +-+-+-+-+-+-+-+-+ . - R times |
| * X: | EXTENDED PID | (OPTIONAL) . |
| * +-+-+-+-+-+-+-+-+ -/ |
| * |
| * PID: The relative Picture ID referred to by this frame. |
| * RS and RQ: The spatial and quality layer IDs. |
| * X: 1 if this layer index has an extended relative Picture ID. |
| */ |
| if (has_ref_idc) { |
| while (ref_fields) { |
| if (len < 1) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| has_ref_field_ext_pic_id = buf[0] & 0x10; |
| |
| /* pass ref. field */ |
| if (has_ref_field_ext_pic_id) { |
| if (len < 2) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* ignore ref. data */ |
| |
| buf += 2; |
| len -= 2; |
| } else { |
| |
| /* ignore ref. data */ |
| |
| buf++; |
| len--; |
| } |
| ref_fields--; |
| } |
| } |
| |
| /* |
| * decode the scalability structure (SS) |
| * |
| * 0 1 2 3 4 5 6 7 |
| * +-+-+-+-+-+-+-+-+ |
| * V: | PATTERN LENGTH| |
| * +-+-+-+-+-+-+-+-+ -\ |
| * | T | S | Q | R | (OPTIONAL) . |
| * +-+-+-+-+-+-+-+-+ -\ . |
| * | PID |X| RS| RQ| (OPTIONAL) . . - PAT. LEN. times |
| * +-+-+-+-+-+-+-+-+ . - R times . |
| * X: | EXTENDED PID | (OPTIONAL) . . |
| * +-+-+-+-+-+-+-+-+ -/ -/ |
| * |
| * PID: The relative Picture ID referred to by this frame. |
| * RS and RQ: The spatial and quality layer IDs. |
| * X: 1 if this layer index has an extended relative Picture ID. |
| */ |
| if (has_ss_data) { |
| avpriv_report_missing_feature(ctx, "VP9 scalability structure data"); |
| return AVERROR(ENOSYS); |
| } |
| |
| /* |
| * decode the scalability update structure (SU) |
| * |
| * spec. is tbd |
| */ |
| if (has_su_data) { |
| avpriv_report_missing_feature(ctx, "VP9 scalability update structure data"); |
| return AVERROR(ENOSYS); |
| } |
| |
| /* |
| * decode the VP9 payload header |
| * |
| * spec. is tbd |
| */ |
| //XXX: implement when specified |
| |
| /* sanity check: 1 byte payload as minimum */ |
| if (len < 1) { |
| av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* start frame buffering with new dynamic buffer */ |
| if (!rtp_vp9_ctx->buf) { |
| /* sanity check: a new frame should have started */ |
| if (first_fragment) { |
| res = avio_open_dyn_buf(&rtp_vp9_ctx->buf); |
| if (res < 0) |
| return res; |
| /* update the timestamp in the frame packet with the one from the RTP packet */ |
| rtp_vp9_ctx->timestamp = *timestamp; |
| } else { |
| /* frame not started yet, need more packets */ |
| return AVERROR(EAGAIN); |
| } |
| } |
| |
| /* write the fragment to the dyn. buffer */ |
| avio_write(rtp_vp9_ctx->buf, buf, len); |
| |
| /* do we need more fragments? */ |
| if (!last_fragment) |
| return AVERROR(EAGAIN); |
| |
| /* close frame buffering and create resulting A/V packet */ |
| res = ff_rtp_finalize_packet(pkt, &rtp_vp9_ctx->buf, st->index); |
| if (res < 0) |
| return res; |
| |
| return 0; |
| } |
| |
| RTPDynamicProtocolHandler ff_vp9_dynamic_handler = { |
| .enc_name = "VP9", |
| .codec_type = AVMEDIA_TYPE_VIDEO, |
| .codec_id = AV_CODEC_ID_VP9, |
| .priv_data_size = sizeof(PayloadContext), |
| .init = vp9_init, |
| .parse_packet = vp9_handle_packet |
| }; |
