H265 codec changes from hvc1 to hev1 - c++

Question

I try to copy mp4 file with hevc video.
Source file have hvc1 codec.
Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668)
After copying the codec gets the value of hev1
Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568)
How can i get hvc1?
I found that ffmpeg can do it with "-tag:v hvc1"
(https://stackoverflow.com/questions/32152090/encode-h265-to-hvc1-codec)
And how to set tag in c++ code (FFMpeg copy streams without transcode)
But it does not effect
My code:
AVOutputFormat *ofmt = NULL;
AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
AVPacket pkt;
const char *in_filename, *out_filename;
int ret, i;
int stream_index = 0;
int *stream_mapping = NULL;
int stream_mapping_size = 0;
if (argc < 3) {
printf("usage: %s input output\n"
"API example program to remux a media file with libavformat and libavcodec.\n"
"The output format is guessed according to the file extension.\n"
"\n", argv[0]);
return 1;
}
in_filename = argv[1];
out_filename = argv[2];
av_register_all();
if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
fprintf(stderr, "Could not open input file '%s'", in_filename);
goto end;
}
if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
fprintf(stderr, "Failed to retrieve input stream information");
goto end;
}
av_dump_format(ifmt_ctx, 0, in_filename, 0);
avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
if (!ofmt_ctx) {
fprintf(stderr, "Could not create output context\n");
ret = AVERROR_UNKNOWN;
goto end;
}
stream_mapping_size = ifmt_ctx->nb_streams;
stream_mapping = (int*)av_mallocz_array(stream_mapping_size, sizeof(*stream_mapping));
if (!stream_mapping) {
ret = AVERROR(ENOMEM);
goto end;
}
ofmt = ofmt_ctx->oformat;
for (i = 0; i < (int)ifmt_ctx->nb_streams; i++) {
AVStream *out_stream;
AVStream *in_stream = ifmt_ctx->streams[i];
AVCodecParameters *in_codecpar = in_stream->codecpar;
AVCodec *decoder = avcodec_find_decoder(in_stream->codecpar->codec_id);
AVCodec *encoder = avcodec_find_encoder(in_stream->codecpar->codec_id);
if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
stream_mapping[i] = -1;
continue;
}
stream_mapping[i] = stream_index++;
out_stream = avformat_new_stream(ofmt_ctx, NULL);
if (!out_stream) {
fprintf(stderr, "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
if (ret < 0) {
fprintf(stderr, "Failed to copy codec parameters\n");
goto end;
}
unsigned int tag = 0;
// for ffmpeg new api 3.x
AVCodecParameters *parameters = out_stream->codecpar;
if (av_codec_get_tag2(ofmt_ctx->oformat->codec_tag, encoder->id, &tag) == 0) {
av_log(NULL, AV_LOG_ERROR, "could not find codec tag for codec id %d, default to 0.\n", encoder->id);
}
parameters->codec_tag = tag;
out_stream->codec = avcodec_alloc_context3(encoder);
// more setting for stream->codec
avcodec_parameters_to_context(out_stream->codec, parameters);
}
av_dump_format(ofmt_ctx, 0, out_filename, 1);
if (!(ofmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
if (ret < 0) {
fprintf(stderr, "Could not open output file '%s'", out_filename);
goto end;
}
}
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
fprintf(stderr, "Error occurred when opening output file\n");
goto end;
}
while (1) {
AVStream *in_stream, *out_stream;
ret = av_read_frame(ifmt_ctx, &pkt);
if (ret < 0)
break;
in_stream = ifmt_ctx->streams[pkt.stream_index];
if (pkt.stream_index >= stream_mapping_size ||
stream_mapping[pkt.stream_index] < 0) {
av_packet_unref(&pkt);
continue;
}
pkt.stream_index = stream_mapping[pkt.stream_index];
out_stream = ofmt_ctx->streams[pkt.stream_index];
log_packet(ifmt_ctx, &pkt, "in");
/* copy packet */
pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
pkt.pos = -1;
log_packet(ofmt_ctx, &pkt, "out");
ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
if (ret < 0) {
fprintf(stderr, "Error muxing packet\n");
break;
}
av_packet_unref(&pkt);
}
av_write_trailer(ofmt_ctx);
end:
avformat_close_input(&ifmt_ctx);
/* close output */
if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
avio_closep(&ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);
av_freep(&stream_mapping);
if (ret < 0 && ret != AVERROR_EOF) {
fprintf(stderr, "Error occurred: %s\n", av_errTOstr(ret).c_str());
return 1;
}
After changes:
out_stream = avformat_new_stream(ofmt_ctx, NULL);
ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
AVCodecParameters *parameters = out_stream->codecpar;
unsigned int tag = 0;
av_codec_get_tag2(ofmt_ctx->oformat->codec_tag, encoder->id, &tag) == 0);
parameters->codec_tag = tag;
out_stream->codec = avcodec_alloc_context3(encoder);
avcodec_parameters_to_context(out_stream->codec, parameters);
if (in_codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
parameters->codec_tag = MKTAG('h', 'v', 'c', '1');
}
}
av_dump_format(ofmt_ctx, 0, out_filename, 1);
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
fprintf(stderr, "Error write header: %s\n", av_errTOstr(ret). c_str());
goto end;
}