From a7829a2a3f8e6ec0b9f2673c11f56916800aeb33 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Mon, 21 Mar 2016 14:23:19 +0100 Subject: h264: reimplement 3aa661ec5 in a more explicit way Instead of handling the problem inside NAL decoding code, add a higher level wrapper function. This should be more robust against future changes (and easier to read). --- libavcodec/h264.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 54 insertions(+), 10 deletions(-) (limited to 'libavcodec/h264.c') diff --git a/libavcodec/h264.c b/libavcodec/h264.c index a90ef6477d..6b95294bbe 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -32,6 +32,7 @@ #include "libavutil/stereo3d.h" #include "libavutil/timer.h" #include "internal.h" +#include "bytestream.h" #include "cabac.h" #include "cabac_functions.h" #include "error_resilience.h" @@ -407,6 +408,55 @@ fail: static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size, int parse_extradata); +/* There are (invalid) samples in the wild with mp4-style extradata, where the + * parameter sets are stored unescaped (i.e. as RBSP). + * This function catches the parameter set decoding failure and tries again + * after escaping it */ +static int decode_extradata_ps_mp4(H264Context *h, const uint8_t *buf, int buf_size) +{ + int ret; + + ret = decode_nal_units(h, buf, buf_size, 1); + if (ret < 0 && !(h->avctx->err_recognition & AV_EF_EXPLODE)) { + GetByteContext gbc; + PutByteContext pbc; + uint8_t *escaped_buf; + int escaped_buf_size; + + av_log(h->avctx, AV_LOG_WARNING, + "SPS decoding failure, trying again after escaping the NAL\n"); + + if (buf_size / 2 >= (INT16_MAX - AV_INPUT_BUFFER_PADDING_SIZE) / 3) + return AVERROR(ERANGE); + escaped_buf_size = buf_size * 3 / 2 + AV_INPUT_BUFFER_PADDING_SIZE; + escaped_buf = av_mallocz(escaped_buf_size); + if (!escaped_buf) + return AVERROR(ENOMEM); + + bytestream2_init(&gbc, buf, buf_size); + bytestream2_init_writer(&pbc, escaped_buf, escaped_buf_size); + + while (bytestream2_get_bytes_left(&gbc)) { + if (bytestream2_get_bytes_left(&gbc) >= 3 && + bytestream2_peek_be24(&gbc) <= 3) { + bytestream2_put_be24(&pbc, 3); + bytestream2_skip(&gbc, 2); + } else + bytestream2_put_byte(&pbc, bytestream2_get_byte(&gbc)); + } + + escaped_buf_size = bytestream2_tell_p(&pbc); + AV_WB16(escaped_buf, escaped_buf_size - 2); + + ret = decode_nal_units(h, escaped_buf, escaped_buf_size, 1); + av_freep(&escaped_buf); + if (ret < 0) + return ret; + } + + return 0; +} + int ff_h264_decode_extradata(H264Context *h) { AVCodecContext *avctx = h->avctx; @@ -433,7 +483,7 @@ int ff_h264_decode_extradata(H264Context *h) nalsize = AV_RB16(p) + 2; if (p - avctx->extradata + nalsize > avctx->extradata_size) return AVERROR_INVALIDDATA; - ret = decode_nal_units(h, p, nalsize, 1); + ret = decode_extradata_ps_mp4(h, p, nalsize); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "Decoding sps %d from avcC failed\n", i); @@ -447,7 +497,7 @@ int ff_h264_decode_extradata(H264Context *h) nalsize = AV_RB16(p) + 2; if (p - avctx->extradata + nalsize > avctx->extradata_size) return AVERROR_INVALIDDATA; - ret = decode_nal_units(h, p, nalsize, 1); + ret = decode_extradata_ps_mp4(h, p, nalsize); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "Decoding pps %d from avcC failed\n", i); @@ -1379,14 +1429,8 @@ again: case NAL_SPS: init_get_bits(&h->gb, ptr, bit_length); ret = ff_h264_decode_seq_parameter_set(h); - if (ret < 0 && h->is_avc && (nalsize != consumed) && nalsize) { - av_log(h->avctx, AV_LOG_DEBUG, - "SPS decoding failure, trying again with the complete NAL\n"); - init_get_bits(&h->gb, buf + buf_index + 1 - consumed, - 8 * (nalsize - 1)); - ff_h264_decode_seq_parameter_set(h); - } - + if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE)) + goto end; break; case NAL_PPS: init_get_bits(&h->gb, ptr, bit_length); -- cgit v1.2.3