mirror of https://github.com/FFmpeg/FFmpeg.git
The code was tested with live555 server. Signed-off-by: Martin Storsjö <martin@martin.st>pull/121/merge
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/*
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* RTP parser for VP9 payload format (draft version 0) - experimental |
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* Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com> |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/intreadwrite.h" |
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#include "avio_internal.h" |
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#include "rtpdec_formats.h" |
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#define RTP_VP9_DESC_REQUIRED_SIZE 1 |
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struct PayloadContext { |
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AVIOContext *buf; |
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uint32_t timestamp; |
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}; |
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static av_cold int vp9_init(AVFormatContext *ctx, int st_index, |
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PayloadContext *data) |
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{ |
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av_log(ctx, AV_LOG_WARNING, |
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"RTP/VP9 support is still experimental\n"); |
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return 0; |
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} |
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static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx, |
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AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
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const uint8_t *buf, int len, uint16_t seq, |
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int flags) |
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{ |
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int has_pic_id, has_layer_idc, has_ref_idc, has_ss_data, has_su_data; |
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av_unused int pic_id = 0, non_key_frame = 0; |
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av_unused int layer_temporal = -1, layer_spatial = -1, layer_quality = -1; |
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int ref_fields = 0, has_ref_field_ext_pic_id = 0; |
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int first_fragment, last_fragment; |
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int rtp_m; |
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int res = 0; |
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/* drop data of previous packets in case of non-continuous (lossy) packet stream */ |
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if (rtp_vp9_ctx->buf && rtp_vp9_ctx->timestamp != *timestamp) |
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ffio_free_dyn_buf(&rtp_vp9_ctx->buf); |
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/* sanity check for size of input packet: 1 byte payload at least */ |
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if (len < RTP_VP9_DESC_REQUIRED_SIZE + 1) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet, got %d bytes\n", len); |
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return AVERROR_INVALIDDATA; |
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} |
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/*
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* decode the required VP9 payload descriptor according to section 4.2 of the spec.: |
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* |
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* 0 1 2 3 4 5 6 7 |
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* +-+-+-+-+-+-+-+-+ |
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* |I|L|F|B|E|V|U|-| (REQUIRED) |
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* +-+-+-+-+-+-+-+-+ |
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* |
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* I: PictureID present |
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* L: Layer indices present |
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* F: Reference indices present |
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* B: Start of VP9 frame |
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* E: End of picture |
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* V: Scalability Structure (SS) present |
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* U: Scalability Structure Update (SU) present |
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*/ |
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has_pic_id = !!(buf[0] & 0x80); |
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has_layer_idc = !!(buf[0] & 0x40); |
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has_ref_idc = !!(buf[0] & 0x20); |
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first_fragment = !!(buf[0] & 0x10); |
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last_fragment = !!(buf[0] & 0x08); |
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has_ss_data = !!(buf[0] & 0x04); |
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has_su_data = !!(buf[0] & 0x02); |
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rtp_m = !!(flags & RTP_FLAG_MARKER); |
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/* sanity check for markers: B should always be equal to the RTP M marker */ |
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if (last_fragment != rtp_m) { |
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av_log(ctx, AV_LOG_ERROR, "Invalid combination of B and M marker (%d != %d)\n", last_fragment, rtp_m); |
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return AVERROR_INVALIDDATA; |
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} |
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/* pass the extensions field */ |
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buf += RTP_VP9_DESC_REQUIRED_SIZE; |
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len -= RTP_VP9_DESC_REQUIRED_SIZE; |
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/*
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* decode the 1-byte/2-byte picture ID: |
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* |
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* 0 1 2 3 4 5 6 7 |
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* +-+-+-+-+-+-+-+-+ |
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* I: |M|PICTURE ID | (RECOMMENDED) |
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* +-+-+-+-+-+-+-+-+ |
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* M: | EXTENDED PID | (RECOMMENDED) |
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* +-+-+-+-+-+-+-+-+ |
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* |
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* M: The most significant bit of the first octet is an extension flag. |
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* PictureID: 8 or 16 bits including the M bit. |
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*/ |
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if (has_pic_id) { |
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if (len < 1) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* check for 1-byte or 2-byte picture index */ |
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if (buf[0] & 0x80) { |
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if (len < 2) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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pic_id = AV_RB16(buf) & 0x7fff; |
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buf += 2; |
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len -= 2; |
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} else { |
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pic_id = buf[0] & 0x7f; |
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buf++; |
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len--; |
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} |
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} |
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/*
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* decode layer indices |
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* |
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* 0 1 2 3 4 5 6 7 |
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* +-+-+-+-+-+-+-+-+ |
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* L: | T | S | Q | R | (CONDITIONALLY RECOMMENDED) |
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* +-+-+-+-+-+-+-+-+ |
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* |
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* T, S and Q are 2-bit indices for temporal, spatial, and quality layers. |
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* If "F" is set in the initial octet, R is 2 bits representing the number |
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* of reference fields this frame refers to. |
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*/ |
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if (has_layer_idc) { |
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if (len < 1) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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layer_temporal = buf[0] & 0xC0; |
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layer_spatial = buf[0] & 0x30; |
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layer_quality = buf[0] & 0x0C; |
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if (has_ref_idc) { |
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ref_fields = buf[0] & 0x03; |
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if (ref_fields) |
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non_key_frame = 1; |
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} |
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buf++; |
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len--; |
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} |
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/*
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* decode the reference fields |
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* |
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* 0 1 2 3 4 5 6 7 |
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* +-+-+-+-+-+-+-+-+ -\
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* F: | PID |X| RS| RQ| (OPTIONAL) . |
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* +-+-+-+-+-+-+-+-+ . - R times |
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* X: | EXTENDED PID | (OPTIONAL) . |
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* +-+-+-+-+-+-+-+-+ -/ |
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* |
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* PID: The relative Picture ID referred to by this frame. |
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* RS and RQ: The spatial and quality layer IDs. |
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* X: 1 if this layer index has an extended relative Picture ID. |
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*/ |
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if (has_ref_idc) { |
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while (ref_fields) { |
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if (len < 1) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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has_ref_field_ext_pic_id = buf[0] & 0x10; |
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/* pass ref. field */ |
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if (has_ref_field_ext_pic_id) { |
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if (len < 2) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* ignore ref. data */ |
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buf += 2; |
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len -= 2; |
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} else { |
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/* ignore ref. data */ |
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buf++; |
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len--; |
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} |
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ref_fields--; |
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} |
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} |
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/*
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* decode the scalability structure (SS) |
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* |
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* 0 1 2 3 4 5 6 7 |
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* +-+-+-+-+-+-+-+-+ |
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* V: | PATTERN LENGTH| |
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* +-+-+-+-+-+-+-+-+ -\
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* | T | S | Q | R | (OPTIONAL) . |
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* +-+-+-+-+-+-+-+-+ -\ . |
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* | PID |X| RS| RQ| (OPTIONAL) . . - PAT. LEN. times |
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* +-+-+-+-+-+-+-+-+ . - R times . |
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* X: | EXTENDED PID | (OPTIONAL) . . |
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* +-+-+-+-+-+-+-+-+ -/ -/ |
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* |
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* PID: The relative Picture ID referred to by this frame. |
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* RS and RQ: The spatial and quality layer IDs. |
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* X: 1 if this layer index has an extended relative Picture ID. |
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*/ |
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if (has_ss_data) { |
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avpriv_report_missing_feature(ctx, "VP9 scalability structure data"); |
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return AVERROR(ENOSYS); |
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} |
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/*
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* decode the scalability update structure (SU) |
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* |
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* spec. is tbd |
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*/ |
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if (has_su_data) { |
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avpriv_report_missing_feature(ctx, "VP9 scalability update structure data"); |
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return AVERROR(ENOSYS); |
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} |
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/*
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* decode the VP9 payload header |
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* |
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* spec. is tbd |
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*/ |
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//XXX: implement when specified
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/* sanity check: 1 byte payload as minimum */ |
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if (len < 1) { |
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av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* start frame buffering with new dynamic buffer */ |
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if (!rtp_vp9_ctx->buf) { |
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/* sanity check: a new frame should have started */ |
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if (first_fragment) { |
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res = avio_open_dyn_buf(&rtp_vp9_ctx->buf); |
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if (res < 0) |
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return res; |
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/* update the timestamp in the frame packet with the one from the RTP packet */ |
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rtp_vp9_ctx->timestamp = *timestamp; |
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} else { |
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/* frame not started yet, need more packets */ |
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return AVERROR(EAGAIN); |
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} |
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} |
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/* write the fragment to the dyn. buffer */ |
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avio_write(rtp_vp9_ctx->buf, buf, len); |
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/* do we need more fragments? */ |
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if (!last_fragment) |
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return AVERROR(EAGAIN); |
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/* close frame buffering and create resulting A/V packet */ |
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res = ff_rtp_finalize_packet(pkt, &rtp_vp9_ctx->buf, st->index); |
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if (res < 0) |
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return res; |
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return 0; |
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} |
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RTPDynamicProtocolHandler ff_vp9_dynamic_handler = { |
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.enc_name = "VP9", |
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.codec_type = AVMEDIA_TYPE_VIDEO, |
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.codec_id = AV_CODEC_ID_VP9, |
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.priv_data_size = sizeof(PayloadContext), |
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.init = vp9_init, |
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.parse_packet = vp9_handle_packet |
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}; |
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