> -----Original Message----- > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of James > Almer > Sent: poniedziaĆek, 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. > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://protect2.fireeye.com/v1/url?k=d9b5596c-b83e4c5f-d9b4d223- > 000babff9bb7-060f807600ae9b45&q=1&e=9deb391f-9dfe-412c-b7d8- > 09a65325c2ec&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 06:36:38 -0700