> -----Original Message----- > From: Dawid Kozinski/Multimedia (PLT) /SRPOL/Staff Engineer/Samsung > Electronics <d.kozin...@samsung.com> > Sent: środa, 7 czerwca 2023 17:41 > To: 'FFmpeg development discussions and patches' <ffmpeg- > de...@ffmpeg.org> > Subject: RE: [FFmpeg-devel] [PATCH v23 04/10] avformat/evc_demuxer: Added > demuxer to handle reading EVC video files > > > > > > > -----Original Message----- > > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of > > James Almer > > Sent: środa, 7 czerwca 2023 15:40 > > To: ffmpeg-devel@ffmpeg.org > > Subject: Re: [FFmpeg-devel] [PATCH v23 04/10] avformat/evc_demuxer: > > Added demuxer to handle reading EVC video files > > > > On 6/7/2023 10:36 AM, Dawid Kozinski/Multimedia (PLT) /SRPOL/Staff > > Engineer/Samsung Electronics wrote: > > > > > > > > > > > >> -----Original Message----- > > >> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of > > >> James Almer > > >> Sent: poniedziałek, 29 maja 2023 15:08 > > >> To: ffmpeg-devel@ffmpeg.org > > >> Subject: Re: [FFmpeg-devel] [PATCH v23 04/10] avformat/evc_demuxer: > > >> Added demuxer to handle reading EVC video files > > >> > > >> On 5/26/2023 7:31 AM, Dawid Kozinski wrote: > > >>> +static int get_temporal_id(const uint8_t *bits, int bits_size) { > > >>> + int temporal_id = 0; > > >>> + short t = 0; > > >>> + > > >>> + if (bits_size >= EVC_NALU_HEADER_SIZE) { > > >>> + unsigned char *p = (unsigned char *)bits; > > >>> + // forbidden_zero_bit > > >>> + if ((p[0] & 0x80) != 0) > > >>> + return -1; > > >>> + > > >>> + for (int i = 0; i < EVC_NALU_HEADER_SIZE; i++) > > >>> + t = (t << 8) | p[i]; > > >> > > >> I think this can be replaced with AV_RB16. > > >> > > >>> + > > >>> + temporal_id = (t >> 6) & 0x0007; > > >>> + } > > >>> + > > >>> + return temporal_id; > > >>> +} > > >> > > >> [...] > > >> > > >>> +static uint32_t read_nal_unit_length(const uint8_t *bits, int > > >>> +bits_size) { > > >>> + uint32_t nalu_len = 0; > > >>> + > > >>> + if (bits_size >= EVC_NALU_LENGTH_PREFIX_SIZE) { > > >>> + > > >>> + int t = 0; > > >>> + unsigned char *p = (unsigned char *)bits; > > >>> + > > >>> + for (int i = 0; i < EVC_NALU_LENGTH_PREFIX_SIZE; i++) > > >>> + t = (t << 8) | p[i]; > > >> > > >> AV_RB32. > > >> > > >>> + > > >>> + nalu_len = t; > > >>> + if (nalu_len == 0) // Invalid bitstream size > > >>> + return 0; > > >>> + } > > >>> + > > >>> + return nalu_len; > > >>> +} > > >> > > >> [...] > > >> > > >>> +static int evc_frame_merge_filter(AVBSFContext *bsf, AVPacket *out) { > > >>> + EVCMergeContext *ctx = bsf->priv_data; > > >>> + AVPacket *in = ctx->in; > > >>> + > > >>> + int free_space = 0; > > >>> + size_t nalu_size = 0; > > >>> + uint8_t *nalu = NULL; > > >>> + int au_end_found = 0; > > >>> + int err; > > >>> + > > >>> + err = ff_bsf_get_packet_ref(bsf, in); > > >>> + if (err < 0) > > >>> + return err; > > >>> + > > >>> + nalu_size = read_nal_unit_length(in->data, > > >> EVC_NALU_LENGTH_PREFIX_SIZE); > > >>> + if(nalu_size <= 0) { > > >>> + av_packet_unref(in); > > >>> + return AVERROR_INVALIDDATA; > > >>> + } > > >>> + > > >>> + nalu = in->data + EVC_NALU_LENGTH_PREFIX_SIZE; > > >>> + nalu_size = in->size - EVC_NALU_LENGTH_PREFIX_SIZE; > > >>> + > > >>> + // NAL unit parsing needed to determine if end of AU was found > > >>> + err = parse_nal_unit(nalu, nalu_size, bsf); > > >>> + if (err < 0) { > > >>> + av_log(bsf, AV_LOG_ERROR, "NAL Unit parsing error\n"); > > >>> + av_packet_unref(in); > > >>> + > > >>> + return err; > > >>> + } > > >>> + > > >>> + au_end_found = end_of_access_unit_found(bsf); > > >>> + > > >>> + free_space = ctx->au_buffer.capacity - ctx->au_buffer.data_size; > > >>> + while( free_space < in->size ) { > > >>> + ctx->au_buffer.capacity *= 2; > > >>> + free_space = ctx->au_buffer.capacity - > > >>> + ctx->au_buffer.data_size; > > >>> + > > >>> + if(free_space >= in->size) { > > >>> + ctx->au_buffer.data = av_realloc(ctx->au_buffer.data, > > >>> + ctx- > > >>> au_buffer.capacity); > > >>> + } > > >>> + } > > >>> + > > >>> + memcpy(ctx->au_buffer.data + ctx->au_buffer.data_size, > > >>> + in->data, > > >>> + in->size); > > >> > > >> This is including the Annex-B's nal_unit_lenght value into the > > >> assembled > > > packet. I > > >> assume libxevd expects this? Also, is it defined as part of the > > >> ISOBMFF encapsulation? Patch 07/10 does not seem to strip it. > > > > > > Could you expand on this topic? > > > What do you mean by "Patch 07/10 does not seem to strip it"? > > > Patch 7/10 expands the implementation of the MOV Muxer to support > > > the EVC stream. > > > The function ff_isom_write_evcc parses the received data, extracts > > > NAL units of types SPS, PPS, APS, SEI, and inserts their contents > > > into the corresponding elements of the arrays array, which is a > > > component of the EVCDecoderConfigurationRecord structure. > > > Additionally, the ff_isom_write_evcc function populates the relevant > > > fields of the EVCDecoderConfigurationRecord structure based on the > > > parsed SPS NAL unit data, and then calls the evcc_write function, > > > which writes the EVCDecoderConfigurationRecord to the stream. > > > > > > It seems that I don't understand what's wrong with our > > > implementation ( I mean MOV muxer for EVC) and it seems I need your > > > help in this matter. I need an explanation of what's wrong and what > > > should be done to fix > > the issue. > > > > I mean the packets that go into ISOBMFF Sample, not the evcc atom. Is > > the encapsulation supposed to include the nal_unit_length from Annex-B? > > The function mov_write_single_packet(s, pkt) receives packets containing the > Access Units (AU) of an EVC stream. Each AU consists of a sequence of NAL > units, each preceded by a 4-byte prefix that contains information about the > length of the NAL unit. The entire AU is then copied to AVIOContext using > avio_write(pb, pkt->data, size). > It seems to me that everything is okay. If I am mistaken, just let me know. As we have also completed all the fixes following your review this is the last thing blocking us from creating a new patchset. > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > https://protect2.fireeye.com/v1/url?k=64932a8f-05183fb9-6492a1c0- > > 74fe485cbff1-9eaddc0975cfe99c&q=1&e=9bd489fd-4417-4f27-9fc0- > > > e7d04e51de8c&u=https%3A%2F%2Fffmpeg.org%2Fmailman%2Flistinfo%2Fffmp > > eg-devel > > > > To unsubscribe, visit link above, or email > > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH v23 04/10] avformat/evc_demuxer: Added demuxer to handle reading EVC video files
Dawid Kozinski/Multimedia (PLT) /SRPOL/Staff Engineer/Samsung Electronics Wed, 07 Jun 2023 09:30:29 -0700