1/* 2 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21#include "libavutil/intreadwrite.h" 22#include "avcodec.h" 23 24typedef struct H264BSFContext { 25 uint8_t length_size; 26 uint8_t first_idr; 27 uint8_t *sps_pps_data; 28 uint32_t size; 29} H264BSFContext; 30 31static void alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size, 32 const uint8_t *sps_pps, uint32_t sps_pps_size, 33 const uint8_t *in, uint32_t in_size) { 34 uint32_t offset = *poutbuf_size; 35 uint8_t nal_header_size = offset ? 3 : 4; 36 37 *poutbuf_size += sps_pps_size+in_size+nal_header_size; 38 *poutbuf = av_realloc(*poutbuf, *poutbuf_size); 39 if (sps_pps) 40 memcpy(*poutbuf+offset, sps_pps, sps_pps_size); 41 memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size); 42 if (!offset) 43 AV_WB32(*poutbuf+sps_pps_size, 1); 44 else { 45 (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0; 46 (*poutbuf+offset+sps_pps_size)[2] = 1; 47 } 48} 49 50static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc, 51 AVCodecContext *avctx, const char *args, 52 uint8_t **poutbuf, int *poutbuf_size, 53 const uint8_t *buf, int buf_size, 54 int keyframe) { 55 H264BSFContext *ctx = bsfc->priv_data; 56 uint8_t unit_type; 57 uint32_t nal_size, cumul_size = 0; 58 59 /* nothing to filter */ 60 if (!avctx->extradata || avctx->extradata_size < 6) { 61 *poutbuf = (uint8_t*) buf; 62 *poutbuf_size = buf_size; 63 return 0; 64 } 65 66 /* retrieve sps and pps NAL units from extradata */ 67 if (!ctx->sps_pps_data) { 68 uint16_t unit_size; 69 uint32_t total_size = 0; 70 uint8_t *out = NULL, unit_nb, sps_done = 0; 71 const uint8_t *extradata = avctx->extradata+4; 72 static const uint8_t nalu_header[4] = {0, 0, 0, 1}; 73 74 /* retrieve length coded size */ 75 ctx->length_size = (*extradata++ & 0x3) + 1; 76 if (ctx->length_size == 3) 77 return AVERROR(EINVAL); 78 79 /* retrieve sps and pps unit(s) */ 80 unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */ 81 if (!unit_nb) { 82 unit_nb = *extradata++; /* number of pps unit(s) */ 83 sps_done++; 84 } 85 while (unit_nb--) { 86 unit_size = AV_RB16(extradata); 87 total_size += unit_size+4; 88 if (extradata+2+unit_size > avctx->extradata+avctx->extradata_size) { 89 av_free(out); 90 return AVERROR(EINVAL); 91 } 92 out = av_realloc(out, total_size); 93 if (!out) 94 return AVERROR(ENOMEM); 95 memcpy(out+total_size-unit_size-4, nalu_header, 4); 96 memcpy(out+total_size-unit_size, extradata+2, unit_size); 97 extradata += 2+unit_size; 98 99 if (!unit_nb && !sps_done++) 100 unit_nb = *extradata++; /* number of pps unit(s) */ 101 } 102 103 ctx->sps_pps_data = out; 104 ctx->size = total_size; 105 ctx->first_idr = 1; 106 } 107 108 *poutbuf_size = 0; 109 *poutbuf = NULL; 110 do { 111 if (ctx->length_size == 1) 112 nal_size = buf[0]; 113 else if (ctx->length_size == 2) 114 nal_size = AV_RB16(buf); 115 else 116 nal_size = AV_RB32(buf); 117 118 buf += ctx->length_size; 119 unit_type = *buf & 0x1f; 120 121 /* prepend only to the first type 5 NAL unit of an IDR picture */ 122 if (ctx->first_idr && unit_type == 5) { 123 alloc_and_copy(poutbuf, poutbuf_size, 124 ctx->sps_pps_data, ctx->size, 125 buf, nal_size); 126 ctx->first_idr = 0; 127 } 128 else { 129 alloc_and_copy(poutbuf, poutbuf_size, 130 NULL, 0, 131 buf, nal_size); 132 if (!ctx->first_idr && unit_type == 1) 133 ctx->first_idr = 1; 134 } 135 136 buf += nal_size; 137 cumul_size += nal_size + ctx->length_size; 138 } while (cumul_size < buf_size); 139 140 return 1; 141} 142 143static void h264_mp4toannexb_close(AVBitStreamFilterContext *bsfc) 144{ 145 H264BSFContext *ctx = bsfc->priv_data; 146 av_freep(&ctx->sps_pps_data); 147} 148 149AVBitStreamFilter h264_mp4toannexb_bsf = { 150 "h264_mp4toannexb", 151 sizeof(H264BSFContext), 152 h264_mp4toannexb_filter, 153 h264_mp4toannexb_close, 154}; 155 156