/* * RTP packetization for H.263 video * Copyright (c) 2012 Martin Storsjo * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavcodec/bitstream.h" #include "libavcodec/put_bits.h" #include "avformat.h" #include "rtpenc.h" struct H263Info { int src; int i; int u; int s; int a; int pb; int tr; }; struct H263State { int gobn; int mba; int hmv1, vmv1, hmv2, vmv2; int quant; }; static void send_mode_a(AVFormatContext *s1, const struct H263Info *info, const uint8_t *buf, int len, int ebits, int m) { RTPMuxContext *s = s1->priv_data; PutBitContext pb; init_put_bits(&pb, s->buf, 32); put_bits(&pb, 1, 0); /* F - 0, mode A */ put_bits(&pb, 1, 0); /* P - 0, normal I/P */ put_bits(&pb, 3, 0); /* SBIT - 0 bits */ put_bits(&pb, 3, ebits); /* EBIT */ put_bits(&pb, 3, info->src); /* SRC - source format */ put_bits(&pb, 1, info->i); /* I - inter/intra */ put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */ put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */ put_bits(&pb, 1, info->a); /* A - advanced prediction */ put_bits(&pb, 4, 0); /* R - reserved */ put_bits(&pb, 2, 0); /* DBQ - 0 */ put_bits(&pb, 3, 0); /* TRB - 0 */ put_bits(&pb, 8, info->tr); /* TR */ flush_put_bits(&pb); memcpy(s->buf + 4, buf, len); ff_rtp_send_data(s1, s->buf, len + 4, m); } static void send_mode_b(AVFormatContext *s1, const struct H263Info *info, const struct H263State *state, const uint8_t *buf, int len, int sbits, int ebits, int m) { RTPMuxContext *s = s1->priv_data; PutBitContext pb; init_put_bits(&pb, s->buf, 64); put_bits(&pb, 1, 1); /* F - 1, mode B */ put_bits(&pb, 1, 0); /* P - 0, mode B */ put_bits(&pb, 3, sbits); /* SBIT - 0 bits */ put_bits(&pb, 3, ebits); /* EBIT - 0 bits */ put_bits(&pb, 3, info->src); /* SRC - source format */ put_bits(&pb, 5, state->quant); /* QUANT - quantizer for the first MB */ put_bits(&pb, 5, state->gobn); /* GOBN - GOB number */ put_bits(&pb, 9, state->mba); /* MBA - MB address */ put_bits(&pb, 2, 0); /* R - reserved */ put_bits(&pb, 1, info->i); /* I - inter/intra */ put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */ put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */ put_bits(&pb, 1, info->a); /* A - advanced prediction */ put_bits(&pb, 7, state->hmv1); /* HVM1 - horizontal motion vector 1 */ put_bits(&pb, 7, state->vmv1); /* VMV1 - vertical motion vector 1 */ put_bits(&pb, 7, state->hmv2); /* HVM2 - horizontal motion vector 2 */ put_bits(&pb, 7, state->vmv2); /* VMV2 - vertical motion vector 2 */ flush_put_bits(&pb); memcpy(s->buf + 8, buf, len); ff_rtp_send_data(s1, s->buf, len + 8, m); } void ff_rtp_send_h263_rfc2190(AVFormatContext *s1, const uint8_t *buf, int size, const uint8_t *mb_info, int mb_info_size) { RTPMuxContext *s = s1->priv_data; int len, sbits = 0, ebits = 0; BitstreamContext bc; struct H263Info info = { 0 }; struct H263State state = { 0 }; int mb_info_pos = 0, mb_info_count = mb_info_size / 12; const uint8_t *buf_base = buf; s->timestamp = s->cur_timestamp; bitstream_init(&bc, buf, size * 8); if (bitstream_read(&bc, 22) == 0x20) { /* Picture Start Code */ info.tr = bitstream_read(&bc, 8); bitstream_skip(&bc, 2); /* PTYPE start, H.261 disambiguation */ bitstream_skip(&bc, 3); /* Split screen, document camera, freeze picture release */ info.src = bitstream_read(&bc, 3); info.i = bitstream_read(&bc, 1); info.u = bitstream_read(&bc, 1); info.s = bitstream_read(&bc, 1); info.a = bitstream_read(&bc, 1); info.pb = bitstream_read(&bc, 1); } while (size > 0) { struct H263State packet_start_state = state; len = FFMIN(s->max_payload_size - 8, size); /* Look for a better place to split the frame into packets. */ if (len < size) { const uint8_t *end = ff_h263_find_resync_marker_reverse(buf, buf + len); len = end - buf; if (len == s->max_payload_size - 8) { /* Skip mb info prior to the start of the current ptr */ while (mb_info_pos < mb_info_count) { uint32_t pos = AV_RL32(&mb_info[12*mb_info_pos])/8; if (pos >= buf - buf_base) break; mb_info_pos++; } /* Find the first mb info past the end pointer */ while (mb_info_pos + 1 < mb_info_count) { uint32_t pos = AV_RL32(&mb_info[12*(mb_info_pos + 1)])/8; if (pos >= end - buf_base) break; mb_info_pos++; } if (mb_info_pos < mb_info_count) { const uint8_t *ptr = &mb_info[12*mb_info_pos]; uint32_t bit_pos = AV_RL32(ptr); uint32_t pos = (bit_pos + 7)/8; if (pos <= end - buf_base) { state.quant = ptr[4]; state.gobn = ptr[5]; state.mba = AV_RL16(&ptr[6]); state.hmv1 = (int8_t) ptr[8]; state.vmv1 = (int8_t) ptr[9]; state.hmv2 = (int8_t) ptr[10]; state.vmv2 = (int8_t) ptr[11]; ebits = 8 * pos - bit_pos; len = pos - (buf - buf_base); mb_info_pos++; } else { av_log(s1, AV_LOG_ERROR, "Unable to split H.263 packet, use -mb_info %d " "or lower.\n", s->max_payload_size - 8); } } else { av_log(s1, AV_LOG_ERROR, "Unable to split H.263 packet, " "use -mb_info %d or -ps 1.\n", s->max_payload_size - 8); } } } if (size > 2 && !buf[0] && !buf[1]) send_mode_a(s1, &info, buf, len, ebits, len == size); else send_mode_b(s1, &info, &packet_start_state, buf, len, sbits, ebits, len == size); if (ebits) { sbits = 8 - ebits; len--; } else { sbits = 0; } buf += len; size -= len; ebits = 0; } }