> -----Original Message----- > From: ffmpeg-devel [mailto:ffmpeg-devel-boun...@ffmpeg.org] On Behalf > Of Mark Thompson > Sent: Monday, December 10, 2018 01:40 > To: ffmpeg-devel@ffmpeg.org > Subject: Re: [FFmpeg-devel] [PATCH, v2] lavc/hevc_parser: add 4 bytes > startcode condition and update FATE > > On 07/12/2018 11:33, Linjie Fu wrote: > > The startcode before VPS,SPS,PPS and the first NALU in an AU is 4 bytes. > > Blindly taking the startcode as 3 bytes will leave 0x00 in last packet > > and may lead to some warnings in parse_nal_units when s->flags is set to > > PARSER_FLAG_COMPLETE_FRAMES. > > > > Add 4 bytes startcode condition in hevc_find_frame_end. > > Modify the code to print the buf_size like in H264 and reduce the > duplication. > > > > Update the FATE checksum for fate-hevc-bsf-mp4toannexb: > > The ref output has redundant 0x00 at the end of the SUFFIX_SEI: > > { 50 01 84 31 00 19 39 77 d0 7b 3f bd 1e 09 38 9a 79 41 > > c0 16 11 da 18 aa 0a db 2b 19 fa 47 3f 0f 67 4a 91 9c a1 > > 12 72 67 d6 f0 8f 66 ee 95 f9 e2 b9 ba 23 9a e8 80 00 } > > > > To verify the output of FATE: > > ffmpeg -i hevc-conformance/WPP_A_ericsson_MAIN10_2.bit -c copy -flags > \ > > +bitexact hevc-mp4.mov > > ffmpeg -i hevc-mp4.mov -c:v copy -fflags +bitexact -f hevc hevc.out > > > > Signed-off-by: Linjie Fu <linjie...@intel.com> > > --- > > [v2]: Update FATE checksum > > > > libavcodec/hevc_parser.c | 15 ++++++++++----- > > tests/fate/hevc.mak | 2 +- > > 2 files changed, 11 insertions(+), 6 deletions(-) > > > > diff --git a/libavcodec/hevc_parser.c b/libavcodec/hevc_parser.c > > index 369d1338d0..aa216e3c8d 100644 > > --- a/libavcodec/hevc_parser.c > > +++ b/libavcodec/hevc_parser.c > > @@ -32,6 +32,7 @@ > > #include "parser.h" > > > > #define START_CODE 0x000001 ///< start_code_prefix_one_3bytes > > +#define START_CODE_4 0x00000001 ///< start_code_4bytes > > (There is no syntax element called "start_code_4bytes".) > > > > > #define IS_IRAP_NAL(nal) (nal->type >= 16 && nal->type <= 23) > > #define IS_IDR_NAL(nal) (nal->type == HEVC_NAL_IDR_W_RADL || nal- > >type == HEVC_NAL_IDR_N_LP) > > @@ -239,7 +240,7 @@ static int parse_nal_units(AVCodecParserContext *s, > const uint8_t *buf, > > } > > } > > /* didn't find a picture! */ > > - av_log(avctx, AV_LOG_ERROR, "missing picture in access unit\n"); > > + av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with > size %d\n", buf_size); > > return -1; > > } > > > > @@ -267,8 +268,7 @@ static int > hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf, > > if ((nut >= HEVC_NAL_VPS && nut <= HEVC_NAL_EOB_NUT) || nut == > HEVC_NAL_SEI_PREFIX || > > (nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) { > > if (pc->frame_start_found) { > > - pc->frame_start_found = 0; > > - return i - 5; > > + goto found; > > } > > } else if (nut <= HEVC_NAL_RASL_R || > > (nut >= HEVC_NAL_BLA_W_LP && nut <= HEVC_NAL_CRA_NUT)) > { > > @@ -277,14 +277,19 @@ static int > hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf, > > if (!pc->frame_start_found) { > > pc->frame_start_found = 1; > > } else { // First slice of next frame found > > - pc->frame_start_found = 0; > > - return i - 5; > > + goto found; > > } > > } > > } > > } > > > > return END_NOT_FOUND; > > + > > +found: > > + pc->frame_start_found = 0; > > + if (((pc->state64 >> 3 * 8) & 0xFFFFFFFF) == START_CODE_4) > > + return i - 6; > > + return i - 5; > > } > > Maybe? Special-casing four bytes doesn't make me feel good about this, > given that leading_zero_8bits can be included as many times as you like at > the beginning of a NAL unit. > > If there are a large number of zeroes between two frames, which packet do > you want them to end up in? This changes it from "all at the end of the first > frame" to "all except the last one at the end of the first frame", and it's > not > immediately obvious to me why that would be the right choice. Why not, for > example, put all of the zeroes into the second frame? > > > > > Thanks, > > - Mark
Hi, Does h264_find_frame_end() has the same issue if the leading_zero_8bits is included for more times? It seems to return i - 4 or i - 5 if the startcode is found, and could not cope with the more leading_zero_8bits situation? ---h264_parser.c Return i - (state & 5) --- And I'm considering to improve this in hevc_parser according to Michael's concern: a parser should produce the same output independant on how the input is cut into bytsstream parts. But this would behave different depending on if the last 0 bytes are still in the current buffer ---hevc_parser.c found: pc->frame_start_found = 0; while ((i - 6 >= 0 && !buf[i - 6]) || (i - 6 < 0 && pc->last_index + i - 6 >= 0 && !pc->buffer[pc->last_index + i - 6])) i--; return i - 5; } --- Thanks, Linjie _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel