open()

bool MayaFlux::IO::FFmpegMuxContext::open	(	const std::string &	filepath,
		const std::string &	explicit_format = {}
	)

Allocate an output context and open the avio layer for writing.

Format is inferred from the filepath extension via avformat_alloc_output_context2. Pass explicit_format to override (e.g. "matroska" to force MKV regardless of extension).

Does NOT write any data to disk. Call write_header() after all stream contexts have been opened on this mux context.

Parameters

filepath	Output file path. Extension determines container.
explicit_format	FFmpeg short format name override; empty = infer.

Returns

True on success; false sets the internal error string.

Definition at line 26 of file FFmpegMuxContext.cpp.

{
    close();
    FFmpegDemuxContext::init_ffmpeg();
 
    const char* fmt = explicit_format.empty() ? nullptr : explicit_format.c_str();
 
    const auto resolved = resolve_write_path(filepath);
 
    int ret = avformat_alloc_output_context2(
        &format_context, nullptr, fmt, resolved.c_str());
 
    if (ret < 0 || !format_context) {
        char errbuf[AV_ERROR_MAX_STRING_SIZE];
        av_strerror(ret, errbuf, sizeof(errbuf));
        m_last_error = "avformat_alloc_output_context2 failed for \""
            + resolved + "\": " + errbuf;
        return false;
    }
 
    if (!(format_context->oformat->flags & AVFMT_NOFILE)) {
        ret = avio_open(&format_context->pb, resolved.c_str(), AVIO_FLAG_WRITE);
        if (ret < 0) {
            char errbuf[AV_ERROR_MAX_STRING_SIZE];
            av_strerror(ret, errbuf, sizeof(errbuf));
            m_last_error = "avio_open failed for \""
                + resolved + "\": " + errbuf;
            avformat_free_context(format_context);
            format_context = nullptr;
            return false;
        }
    }
 
    return true;
}

References close(), format_context, MayaFlux::IO::FFmpegDemuxContext::init_ffmpeg(), m_last_error, and MayaFlux::IO::resolve_write_path().

Referenced by MayaFlux::IO::SoundFileWriter::worker_loop(), and MayaFlux::IO::VideoFileWriter::worker_loop().

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