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; uint8_t unit_type; int32_t nal_size; uint32_t cumul_size = 0; const uint8_t *buf_end = buf + buf_size; /* 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) { uint16_t unit_size; uint64_t total_size = 0; uint8_t *out = NULL, unit_nb, sps_done = 0; const uint8_t *extradata = avctx->extradata+4; static const uint8_t nalu_header[4] = {0, 0, 0, 1}; /* retrieve length coded size */ ctx->length_size = (*extradata++ & 0x3) + 1; if (ctx->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++; } while (unit_nb--) { void *tmp; unit_size = AV_RB16(extradata); total_size += unit_size+4; if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE || extradata+2+unit_size > avctx->extradata+avctx->extradata_size) { av_free(out); return AVERROR(EINVAL); } tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE); if (!tmp) { av_free(out); return AVERROR(ENOMEM); } out = tmp; 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) */ } memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE); av_free(avctx->extradata); avctx->extradata = out; avctx->extradata_size = total_size; ctx->first_idr = 1; ctx->extradata_parsed = 1; } *poutbuf_size = 0; *poutbuf = NULL; do { if (buf + ctx->length_size > buf_end) goto fail; if (ctx->length_size == 1) { nal_size = buf[0]; } else if (ctx->length_size == 2) { nal_size = AV_RB16(buf); } else nal_size = AV_RB32(buf); buf += ctx->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 (ctx->first_idr && unit_type == 5) { if (alloc_and_copy(poutbuf, poutbuf_size, avctx->extradata, avctx->extradata_size, buf, nal_size) < 0) goto fail; ctx->first_idr = 0; } else { if (alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size) < 0) goto fail; if (!ctx->first_idr && unit_type == 1) ctx->first_idr = 1; } 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 AVERROR(EINVAL); }