libavcodec/h264_mp4toannexb_bsf.c

   1 /*
   2  * H.264 MP4 to Annex B byte stream format filter
   3  * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <string.h>
  23
  24 #include "libavutil/intreadwrite.h"
  25 #include "libavutil/mem.h"
  26 #include "avcodec.h"
  27
  28 typedef struct H264BSFContext {
  29     uint8_t  length_size;
  30     uint8_t  first_idr;
  31     int      extradata_parsed;
  32 } H264BSFContext;
  33
  34 static int alloc_and_copy(uint8_t **poutbuf,          int *poutbuf_size,
  35                           const uint8_t *sps_pps, uint32_t sps_pps_size,
  36                           const uint8_t *in,      uint32_t in_size) {
  37     uint32_t offset = *poutbuf_size;
  38     uint8_t nal_header_size = offset ? 3 : 4;
  39     void *tmp;
  40
  41     *poutbuf_size += sps_pps_size+in_size+nal_header_size;
  42     tmp = av_realloc(*poutbuf, *poutbuf_size);
  43     if (!tmp)
  44         return AVERROR(ENOMEM);
  45     *poutbuf = tmp;
  46     if (sps_pps)
  47         memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
  48     memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
  49     if (!offset) {
  50         AV_WB32(*poutbuf+sps_pps_size, 1);
  51     } else {
  52         (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
  53         (*poutbuf+offset+sps_pps_size)[2] = 1;
  54     }
  55
  56     return 0;
  57 }
  58
  59 static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
  60                                    AVCodecContext *avctx, const char *args,
  61                                    uint8_t  **poutbuf, int *poutbuf_size,
  62                                    const uint8_t *buf, int      buf_size,
  63                                    int keyframe) {
  64     H264BSFContext *ctx = bsfc->priv_data;
  65     uint8_t unit_type;
  66     int32_t nal_size;
  67     uint32_t cumul_size = 0;
  68     const uint8_t *buf_end = buf + buf_size;
  69
  70     /* nothing to filter */
  71     if (!avctx->extradata || avctx->extradata_size < 6) {
  72         *poutbuf = (uint8_t*) buf;
  73         *poutbuf_size = buf_size;
  74         return 0;
  75     }
  76
  77     /* retrieve sps and pps NAL units from extradata */
  78     if (!ctx->extradata_parsed) {
  79         uint16_t unit_size;
  80         uint64_t total_size = 0;
  81         uint8_t *out = NULL, unit_nb, sps_done = 0, sps_seen = 0, pps_seen = 0;
  82         const uint8_t *extradata = avctx->extradata+4;
  83         static const uint8_t nalu_header[4] = {0, 0, 0, 1};
  84
  85         /* retrieve length coded size */
  86         ctx->length_size = (*extradata++ & 0x3) + 1;
  87         if (ctx->length_size == 3)
  88             return AVERROR(EINVAL);
  89
  90         /* retrieve sps and pps unit(s) */
  91         unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
  92         if (!unit_nb) {
  93             unit_nb = *extradata++; /* number of pps unit(s) */
  94             sps_done++;
  95
  96             if (unit_nb)
  97                 pps_seen = 1;
  98         } else {
  99             sps_seen = 1;
 100         }
 101
 102         while (unit_nb--) {
 103             void *tmp;
 104
 105             unit_size = AV_RB16(extradata);
 106             total_size += unit_size+4;
 107             if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE ||
 108                 extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
 109                 av_free(out);
 110                 return AVERROR(EINVAL);
 111             }
 112             tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE);
 113             if (!tmp) {
 114                 av_free(out);
 115                 return AVERROR(ENOMEM);
 116             }
 117             out = tmp;
 118             memcpy(out+total_size-unit_size-4, nalu_header, 4);
 119             memcpy(out+total_size-unit_size,   extradata+2, unit_size);
 120             extradata += 2+unit_size;
 121
 122             if (!unit_nb && !sps_done++) {
 123                 unit_nb = *extradata++; /* number of pps unit(s) */
 124                 if (unit_nb)
 125                     pps_seen = 1;
 126             }
 127         }
 128
 129         if(out)
 130             memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 131
 132         if (!sps_seen)
 133             av_log(avctx, AV_LOG_WARNING, "Warning: SPS NALU missing or invalid. The resulting stream may not play.\n");
 134         if (!pps_seen)
 135             av_log(avctx, AV_LOG_WARNING, "Warning: PPS NALU missing or invalid. The resulting stream may not play.\n");
 136
 137         av_free(avctx->extradata);
 138         avctx->extradata      = out;
 139         avctx->extradata_size = total_size;
 140         ctx->first_idr        = 1;
 141         ctx->extradata_parsed = 1;
 142     }
 143
 144     *poutbuf_size = 0;
 145     *poutbuf = NULL;
 146     do {
 147         if (buf + ctx->length_size > buf_end)
 148             goto fail;
 149
 150         if (ctx->length_size == 1) {
 151             nal_size = buf[0];
 152         } else if (ctx->length_size == 2) {
 153             nal_size = AV_RB16(buf);
 154         } else
 155             nal_size = AV_RB32(buf);
 156
 157         buf += ctx->length_size;
 158         unit_type = *buf & 0x1f;
 159
 160         if (buf + nal_size > buf_end || nal_size < 0)
 161             goto fail;
 162
 163         /* prepend only to the first type 5 NAL unit of an IDR picture */
 164         if (ctx->first_idr && unit_type == 5) {
 165             if (alloc_and_copy(poutbuf, poutbuf_size,
 166                                avctx->extradata, avctx->extradata_size,
 167                                buf, nal_size) < 0)
 168                 goto fail;
 169             ctx->first_idr = 0;
 170         } else {
 171             if (alloc_and_copy(poutbuf, poutbuf_size,
 172                                NULL, 0,
 173                                buf, nal_size) < 0)
 174                 goto fail;
 175             if (!ctx->first_idr && unit_type == 1)
 176                 ctx->first_idr = 1;
 177         }
 178
 179         buf += nal_size;
 180         cumul_size += nal_size + ctx->length_size;
 181     } while (cumul_size < buf_size);
 182
 183     return 1;
 184
 185 fail:
 186     av_freep(poutbuf);
 187     *poutbuf_size = 0;
 188     return AVERROR(EINVAL);
 189 }
 190
 191 AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
 192     "h264_mp4toannexb",
 193     sizeof(H264BSFContext),
 194     h264_mp4toannexb_filter,
 195 };