mirror of https://github.com/FFmpeg/FFmpeg.git
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/*
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* RTP packetizer for HEVC/H.265 payload format (draft version 6) |
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* Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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 "avformat.h" |
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#include "avc.h" |
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#include "rtpenc.h" |
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#define RTP_HEVC_HEADERS_SIZE 3 |
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static const uint8_t *avc_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size) |
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{ |
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unsigned int res = 0; |
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/* is the given data big enough for 1 NAL unit? */ |
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if (end - start < nal_length_size) |
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return NULL; |
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while (nal_length_size--) |
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res = (res << 8) | *start++; |
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if (res > end - start) |
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return NULL; |
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return start + res; |
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} |
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static void nal_send(AVFormatContext *ctx, const uint8_t *buf, int len, int last_packet_of_frame) |
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{ |
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RTPMuxContext *rtp_ctx = ctx->priv_data; |
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int rtp_payload_size = rtp_ctx->max_payload_size - RTP_HEVC_HEADERS_SIZE; |
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int nal_type = (buf[0] >> 1) & 0x3F; |
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/* send it as one single NAL unit? */ |
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if (len <= rtp_ctx->max_payload_size) { |
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/* use the original NAL unit buffer and transmit it as RTP payload */ |
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ff_rtp_send_data(ctx, buf, len, last_packet_of_frame); |
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} else { |
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/*
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create the HEVC payload header and transmit the buffer as fragmentation units (FU) |
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0 1 |
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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|F| Type | LayerId | TID | |
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+-------------+-----------------+ |
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F = 0 |
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Type = 49 (fragmentation unit (FU)) |
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LayerId = 0 |
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TID = 1 |
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*/ |
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rtp_ctx->buf[0] = 49 << 1; |
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rtp_ctx->buf[1] = 1; |
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/*
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create the FU header |
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0 1 2 3 4 5 6 7 |
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+-+-+-+-+-+-+-+-+ |
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|S|E| FuType | |
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+---------------+ |
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S = variable |
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E = variable |
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FuType = NAL unit type |
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*/ |
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rtp_ctx->buf[2] = nal_type; |
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/* set the S bit: mark as start fragment */ |
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rtp_ctx->buf[2] |= 1 << 7; |
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/* pass the original NAL header */ |
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buf += 2; |
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len -= 2; |
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while (len + RTP_HEVC_HEADERS_SIZE > rtp_ctx->max_payload_size) { |
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/* complete and send current RTP packet */ |
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memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, rtp_payload_size); |
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ff_rtp_send_data(ctx, rtp_ctx->buf, rtp_ctx->max_payload_size, 0); |
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buf += rtp_payload_size; |
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len -= rtp_payload_size; |
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/* reset the S bit */ |
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rtp_ctx->buf[2] &= ~(1 << 7); |
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} |
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/* set the E bit: mark as last fragment */ |
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rtp_ctx->buf[2] |= 1 << 6; |
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/* complete and send last RTP packet */ |
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memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, len); |
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ff_rtp_send_data(ctx, rtp_ctx->buf, len + 2, last_packet_of_frame); |
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} |
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} |
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void ff_rtp_send_hevc(AVFormatContext *ctx, const uint8_t *frame_buf, int frame_size) |
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{ |
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const uint8_t *next_NAL_unit; |
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const uint8_t *buf_ptr, *buf_end = frame_buf + frame_size; |
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RTPMuxContext *rtp_ctx = ctx->priv_data; |
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/* use the default 90 KHz time stamp */ |
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rtp_ctx->timestamp = rtp_ctx->cur_timestamp; |
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if (rtp_ctx->nal_length_size) |
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buf_ptr = avc_mp4_find_startcode(frame_buf, buf_end, rtp_ctx->nal_length_size) ? frame_buf : buf_end; |
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else |
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buf_ptr = ff_avc_find_startcode(frame_buf, buf_end); |
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/* find all NAL units and send them as separate packets */ |
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while (buf_ptr < buf_end) { |
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if (rtp_ctx->nal_length_size) { |
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next_NAL_unit = avc_mp4_find_startcode(buf_ptr, buf_end, rtp_ctx->nal_length_size); |
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if (!next_NAL_unit) |
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next_NAL_unit = buf_end; |
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buf_ptr += rtp_ctx->nal_length_size; |
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} else { |
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while (!*(buf_ptr++)) ; |
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next_NAL_unit = ff_avc_find_startcode(buf_ptr, buf_end); |
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} |
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/* send the next NAL unit */ |
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nal_send(ctx, buf_ptr, next_NAL_unit - buf_ptr, next_NAL_unit == buf_end); |
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/* jump to the next NAL unit */ |
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buf_ptr = next_NAL_unit; |
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} |
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} |
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