/* * H.264 MP4 to Annex B byte stream format filter * Copyright (c) 2007 Benoit Fouet * * This file is part of FFmpeg. * * FFmpeg 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. * * FFmpeg 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 FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include "libavutil/intreadwrite.h" #include "libavutil/mem.h" #include "avcodec.h" typedef struct H264BSFContext { int32_t sps_offset; int32_t pps_offset; uint8_t length_size; uint8_t new_idr; uint8_t idr_sps_seen; uint8_t idr_pps_seen; int extradata_parsed; /* When private_spspps is zero then spspps_buf points to global extradata and bsf does replace a global extradata to own-allocated version (default behaviour). When private_spspps is non-zero the bsf uses a private version of spspps buf. This mode necessary when bsf uses in decoder, else bsf has issues after decoder re-initialization. Use the "private_spspps_buf" argument to activate this mode. */ int private_spspps; uint8_t *spspps_buf; uint32_t spspps_size; } H264BSFContext; static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size, const uint8_t *sps_pps, uint32_t sps_pps_size, const uint8_t *in, uint32_t in_size) { uint32_t offset = *poutbuf_size; uint8_t nal_header_size = offset ? 3 : 4; int err; *poutbuf_size += sps_pps_size + in_size + nal_header_size; if ((err = av_reallocp(poutbuf, *poutbuf_size + AV_INPUT_BUFFER_PADDING_SIZE)) < 0) { *poutbuf_size = 0; return err; } if (sps_pps) memcpy(*poutbuf + offset, sps_pps, sps_pps_size); memcpy(*poutbuf + sps_pps_size + nal_header_size + offset, in, in_size); if (!offset) { AV_WB32(*poutbuf + sps_pps_size, 1); } else { (*poutbuf + offset + sps_pps_size)[0] = (*poutbuf + offset + sps_pps_size)[1] = 0; (*poutbuf + offset + sps_pps_size)[2] = 1; } return 0; } static int h264_extradata_to_annexb(H264BSFContext *ctx, AVCodecContext *avctx, const int padding) { uint16_t unit_size; uint64_t total_size = 0; uint8_t *out = NULL, unit_nb, sps_done = 0, sps_seen = 0, pps_seen = 0; const uint8_t *extradata = avctx->extradata + 4; static const uint8_t nalu_header[4] = { 0, 0, 0, 1 }; int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size ctx->sps_offset = ctx->pps_offset = -1; /* retrieve sps and pps unit(s) */ unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */ if (!unit_nb) { goto pps; } else { ctx->sps_offset = 0; sps_seen = 1; } while (unit_nb--) { int err; unit_size = AV_RB16(extradata); total_size += unit_size + 4; if (total_size > INT_MAX - padding) { av_log(avctx, AV_LOG_ERROR, "Too big extradata size, corrupted stream or invalid MP4/AVCC bitstream\n"); av_free(out); return AVERROR(EINVAL); } if (extradata + 2 + unit_size > avctx->extradata + avctx->extradata_size) { av_log(avctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, " "corrupted stream or invalid MP4/AVCC bitstream\n"); av_free(out); return AVERROR(EINVAL); } if ((err = av_reallocp(&out, total_size + padding)) < 0) return err; memcpy(out + total_size - unit_size - 4, nalu_header, 4); memcpy(out + total_size - unit_size, extradata + 2, unit_size); extradata += 2 + unit_size; pps: if (!unit_nb && !sps_done++) { unit_nb = *extradata++; /* number of pps unit(s) */ if (unit_nb) { ctx->pps_offset = total_size; pps_seen = 1; } } } if (out) memset(out + total_size, 0, padding); if (!sps_seen) av_log(avctx, AV_LOG_WARNING, "Warning: SPS NALU missing or invalid. " "The resulting stream may not play.\n"); if (!pps_seen) av_log(avctx, AV_LOG_WARNING, "Warning: PPS NALU missing or invalid. " "The resulting stream may not play.\n"); if (!ctx->private_spspps) { av_free(avctx->extradata); avctx->extradata = out; avctx->extradata_size = total_size; } ctx->spspps_buf = out; ctx->spspps_size = total_size; return length_size; } static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int keyframe) { H264BSFContext *ctx = bsfc->priv_data; int i; uint8_t unit_type; int32_t nal_size; uint32_t cumul_size = 0; const uint8_t *buf_end = buf + buf_size; int ret = 0; /* nothing to filter */ if (!avctx->extradata || avctx->extradata_size < 6) { *poutbuf = (uint8_t *)buf; *poutbuf_size = buf_size; return 0; } /* retrieve sps and pps NAL units from extradata */ if (!ctx->extradata_parsed) { if (args && strstr(args, "private_spspps_buf")) ctx->private_spspps = 1; ret = h264_extradata_to_annexb(ctx, avctx, AV_INPUT_BUFFER_PADDING_SIZE); if (ret < 0) return ret; ctx->length_size = ret; ctx->new_idr = 1; ctx->idr_sps_seen = 0; ctx->idr_pps_seen = 0; ctx->extradata_parsed = 1; } *poutbuf_size = 0; *poutbuf = NULL; do { ret= AVERROR(EINVAL); if (buf + ctx->length_size > buf_end) goto fail; for (nal_size = 0, i = 0; ilength_size; i++) nal_size = (nal_size << 8) | buf[i]; buf += ctx->length_size; unit_type = *buf & 0x1f; if (nal_size > buf_end - buf || nal_size < 0) goto fail; if (unit_type == 7) ctx->idr_sps_seen = ctx->new_idr = 1; else if (unit_type == 8) { ctx->idr_pps_seen = ctx->new_idr = 1; /* if SPS has not been seen yet, prepend the AVCC one to PPS */ if (!ctx->idr_sps_seen) { if (ctx->sps_offset == -1) av_log(avctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n"); else { if ((ret = alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf + ctx->sps_offset, ctx->pps_offset != -1 ? ctx->pps_offset : ctx->spspps_size - ctx->sps_offset, buf, nal_size)) < 0) goto fail; ctx->idr_sps_seen = 1; goto next_nal; } } } /* if this is a new IDR picture following an IDR picture, reset the idr flag. * Just check first_mb_in_slice to be 0 as this is the simplest solution. * This could be checking idr_pic_id instead, but would complexify the parsing. */ if (!ctx->new_idr && unit_type == 5 && (buf[1] & 0x80)) ctx->new_idr = 1; /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */ if (ctx->new_idr && unit_type == 5 && !ctx->idr_sps_seen && !ctx->idr_pps_seen) { if ((ret=alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf, ctx->spspps_size, buf, nal_size)) < 0) goto fail; ctx->new_idr = 0; /* if only SPS has been seen, also insert PPS */ } else if (ctx->new_idr && unit_type == 5 && ctx->idr_sps_seen && !ctx->idr_pps_seen) { if (ctx->pps_offset == -1) { av_log(avctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n"); if ((ret = alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size)) < 0) goto fail; } else if ((ret = alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf + ctx->pps_offset, ctx->spspps_size - ctx->pps_offset, buf, nal_size)) < 0) goto fail; } else { if ((ret=alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size)) < 0) goto fail; if (!ctx->new_idr && unit_type == 1) { ctx->new_idr = 1; ctx->idr_sps_seen = 0; ctx->idr_pps_seen = 0; } } next_nal: buf += nal_size; cumul_size += nal_size + ctx->length_size; } while (cumul_size < buf_size); return 1; fail: av_freep(poutbuf); *poutbuf_size = 0; return ret; } static void h264_mp4toannexb_filter_close(AVBitStreamFilterContext *bsfc) { H264BSFContext *ctx = bsfc->priv_data; if (ctx->private_spspps) av_freep(&ctx->spspps_buf); } AVBitStreamFilter ff_h264_mp4toannexb_bsf = { .name = "h264_mp4toannexb", .priv_data_size = sizeof(H264BSFContext), .filter = h264_mp4toannexb_filter, .close = h264_mp4toannexb_filter_close, };