/* * H.264 MP4 to Annex B byte stream format filter * Copyright (c) 2007 Benoit Fouet * * 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 #include "libavutil/intreadwrite.h" #include "libavutil/mem.h" #include "avcodec.h" #include "bsf.h" typedef struct H264BSFContext { uint8_t length_size; uint8_t first_idr; int extradata_parsed; } H264BSFContext; static int alloc_and_copy(AVPacket *out, const uint8_t *sps_pps, uint32_t sps_pps_size, const uint8_t *in, uint32_t in_size) { uint32_t offset = out->size; uint8_t nal_header_size = offset ? 3 : 4; int err; err = av_grow_packet(out, sps_pps_size + in_size + nal_header_size); if (err < 0) return err; if (sps_pps) memcpy(out->data + offset, sps_pps, sps_pps_size); memcpy(out->data + sps_pps_size + nal_header_size + offset, in, in_size); if (!offset) { AV_WB32(out->data + sps_pps_size, 1); } else { (out->data + offset + sps_pps_size)[0] = (out->data + offset + sps_pps_size)[1] = 0; (out->data + offset + sps_pps_size)[2] = 1; } return 0; } static int h264_extradata_to_annexb(AVBSFContext *ctx, 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 = ctx->par_in->extradata + 4; static const uint8_t nalu_header[4] = { 0, 0, 0, 1 }; int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size if (length_size == 3) return AVERROR(EINVAL); /* retrieve sps and pps unit(s) */ unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */ if (!unit_nb) { unit_nb = *extradata++; /* number of pps unit(s) */ sps_done++; if (unit_nb) pps_seen = 1; } else { sps_seen = 1; } while (unit_nb--) { int err; unit_size = AV_RB16(extradata); total_size += unit_size + 4; if (total_size > INT_MAX - padding || extradata + 2 + unit_size > ctx->par_in->extradata + ctx->par_in->extradata_size) { 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; if (!unit_nb && !sps_done++) { unit_nb = *extradata++; /* number of pps unit(s) */ if (unit_nb) pps_seen = 1; } } if (out) memset(out + total_size, 0, AV_INPUT_BUFFER_PADDING_SIZE); if (!sps_seen) av_log(ctx, AV_LOG_WARNING, "Warning: SPS NALU missing or invalid. " "The resulting stream may not play.\n"); if (!pps_seen) av_log(ctx, AV_LOG_WARNING, "Warning: PPS NALU missing or invalid. " "The resulting stream may not play.\n"); av_freep(&ctx->par_out->extradata); ctx->par_out->extradata = out; ctx->par_out->extradata_size = total_size; return length_size; } static int h264_mp4toannexb_init(AVBSFContext *ctx) { H264BSFContext *s = ctx->priv_data; int extra_size = ctx->par_in->extradata_size; int ret; /* retrieve sps and pps NAL units from extradata */ if (!extra_size || (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) || (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) { av_log(ctx, AV_LOG_VERBOSE, "The input looks like it is Annex B already\n"); } else if (extra_size >= 6) { ret = h264_extradata_to_annexb(ctx, AV_INPUT_BUFFER_PADDING_SIZE); if (ret < 0) return ret; s->length_size = ret; s->first_idr = 1; s->extradata_parsed = 1; } else { av_log(ctx, AV_LOG_ERROR, "Invalid extradata size: %d\n", extra_size); return AVERROR_INVALIDDATA; } return 0; } static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out) { H264BSFContext *s = ctx->priv_data; AVPacket *in; uint8_t unit_type; int32_t nal_size; uint32_t cumul_size = 0; const uint8_t *buf; const uint8_t *buf_end; int buf_size; int ret = 0; ret = ff_bsf_get_packet(ctx, &in); if (ret < 0) return ret; /* nothing to filter */ if (!s->extradata_parsed) { av_packet_move_ref(out, in); av_packet_free(&in); return 0; } buf = in->data; buf_size = in->size; buf_end = in->data + in->size; do { if (buf + s->length_size > buf_end) goto fail; if (s->length_size == 1) { nal_size = buf[0]; } else if (s->length_size == 2) { nal_size = AV_RB16(buf); } else nal_size = AV_RB32(buf); buf += s->length_size; unit_type = *buf & 0x1f; if (buf + nal_size > buf_end || nal_size < 0) goto fail; /* prepend only to the first type 5 NAL unit of an IDR picture */ if (s->first_idr && unit_type == 5) { if (alloc_and_copy(out, ctx->par_out->extradata, ctx->par_out->extradata_size, buf, nal_size) < 0) goto fail; s->first_idr = 0; } else { if (alloc_and_copy(out, NULL, 0, buf, nal_size) < 0) goto fail; if (!s->first_idr && unit_type == 1) s->first_idr = 1; } buf += nal_size; cumul_size += nal_size + s->length_size; } while (cumul_size < buf_size); ret = av_packet_copy_props(out, in); if (ret < 0) goto fail; fail: if (ret < 0) av_packet_unref(out); av_packet_free(&in); return ret; } static const enum AVCodecID codec_ids[] = { AV_CODEC_ID_H264, AV_CODEC_ID_NONE, }; const AVBitStreamFilter ff_h264_mp4toannexb_bsf = { .name = "h264_mp4toannexb", .priv_data_size = sizeof(H264BSFContext), .init = h264_mp4toannexb_init, .filter = h264_mp4toannexb_filter, .codec_ids = codec_ids, };