ffmpeg_base.cc

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/*
 * Copyright (C) 2017-2026 Norbert Schlia (nschlia@oblivion-software.de)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * On Debian systems, the complete text of the GNU General Public License
 * Version 3 can be found in `/usr/share/common-licenses/GPL-3'.
 */
 
#ifdef __cplusplus
extern "C" {
#endif
// Disable annoying warnings outside our code
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#pragma GCC diagnostic ignored "-Wsign-conversion"
#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/pixdesc.h>
#include <libavutil/channel_layout.h>
#include <libavcodec/avcodec.h>
#pragma GCC diagnostic pop
#ifdef __cplusplus
}
#endif
 
#include "ffmpeg_base.h"
#include "logging.h"
 
 
FFmpeg_Base::FFmpeg_Base()
    : m_virtualfile(nullptr)
{
}
 
 
void FFmpeg_Base::video_stream_setup(AVCodecContext *output_codec_ctx, AVStream* output_stream, AVCodecContext *input_codec_ctx, AVRational framerate, AVPixelFormat  enc_hw_pix_fmt) const
{
    AVRational time_base_tbn;
    AVRational time_base_tbc;
 
    if (!framerate.num || !framerate.den)
    {
        framerate.num = 25;
        framerate.den = 1;
        Logging::warning(nullptr, "No information about the input framerate is available. Falling back to a default value of 25fps for the output stream.");
    }
 
    // timebase: This is the fundamental unit of time (in seconds) in terms
    // of which frame timestamps are represented. For fixed-fps content,
    // timebase should be 1/framerate and timestamp increments should be
    // identical to 1.
    //time_base                                 = m_in.m_pVideo_stream->time_base;
 
    // tbn: must be set differently for the target format. Otherwise produces strange results.
    switch (output_codec_ctx->codec_id)
    {
    case AV_CODEC_ID_THEORA:        // ogg
    case AV_CODEC_ID_MPEG1VIDEO:
    case AV_CODEC_ID_MPEG2VIDEO:
    {
        time_base_tbn                           = av_inv_q(framerate);
        time_base_tbc                           = time_base_tbn;
        break;
    }
    case AV_CODEC_ID_VP9:           // webm
    {
        time_base_tbn.num                       = 1;
        time_base_tbn.den                       = 1000;
        time_base_tbc                           = time_base_tbn;
        break;
    }
    case AV_CODEC_ID_H264:          // h264
    case AV_CODEC_ID_H265:          // h265
    {
        time_base_tbn.num                       = 1;
        time_base_tbn.den                       = 90000;
        time_base_tbc                           = av_inv_q(framerate);
        break;
    }
    default:                        // mp4 and all others
    {
        time_base_tbn.num                       = 1;
        time_base_tbn.den                       = 90000;
        time_base_tbc                           = time_base_tbn;
        break;
    }
    }
 
    // tbn
    output_stream->time_base                    = time_base_tbn;
    // tbc
    output_codec_ctx->time_base                 = time_base_tbc;
 
    // tbr
    // output_stream->r_frame_rate              = m_in.m_pVideo_stream->r_frame_rate;
    output_stream->r_frame_rate                 = framerate;
 
    // fps
    output_stream->avg_frame_rate               = framerate;
    // output_codec_ctx->framerate                 = framerate;
 
    if (enc_hw_pix_fmt == AV_PIX_FMT_NONE)
    {
        // Automatic pix_fmt selection
        int loss = 0;
 
        AVPixelFormat  src_pix_fmt                  = input_codec_ctx->pix_fmt;
#if LAVC_USE_SUPPORTED_CFG
        {
        const enum AVPixelFormat *pix_list = nullptr;
        int npix = 0;
        int ret_cfg = avcodec_get_supported_config(output_codec_ctx, output_codec_ctx->codec,
                                                   AV_CODEC_CONFIG_PIX_FORMAT,
                                                   0, (const void**)&pix_list, &npix);
        if (ret_cfg >= 0 && pix_list && npix > 0)
        {
            int alpha = 0;
            enc_hw_pix_fmt = avcodec_find_best_pix_fmt_of_list(pix_list, src_pix_fmt, alpha, &loss);
        }
    }
#else
        if (output_codec_ctx->codec->pix_fmts != nullptr)
        {
            int alpha = 0;
            enc_hw_pix_fmt = avcodec_find_best_pix_fmt_of_list(output_codec_ctx->codec->pix_fmts, src_pix_fmt, alpha, &loss);
        }
#endif
 
        if (enc_hw_pix_fmt == AV_PIX_FMT_NONE)
        {
            // Fail safe if avcodec_find_best_pix_fmt_of_list has no idea what to use.
            switch (output_codec_ctx->codec_id)
            {
            case AV_CODEC_ID_PRORES:       // mov/prores
            {
                //  yuva444p10le
                // ProRes 4:4:4 if the source is RGB and ProRes 4:2:2 if the source is YUV.
                enc_hw_pix_fmt                         = AV_PIX_FMT_YUV422P10LE;
                break;
            }
            default:                        // all others
            {
                // At this moment the output format must be AV_PIX_FMT_YUV420P;
                enc_hw_pix_fmt                         = AV_PIX_FMT_YUV420P;
                break;
            }
            }
        }
    }
 
    output_codec_ctx->pix_fmt                   = enc_hw_pix_fmt;
    output_codec_ctx->gop_size                  = 12;   // emit one intra frame every twelve frames at most
}
 
int FFmpeg_Base::dict_set_with_check(AVDictionary **pm, const char *key, const char *value, int flags, const char * filename, bool nodelete) const
{
    if (nodelete && !*value)
    {
        return 0;
    }
 
    int ret = av_dict_set(pm, key, value, flags);
 
    if (ret < 0)
    {
        Logging::error(filename, "Error setting dictionary option key(%1)='%2' (error '%3').", key, value, ffmpeg_geterror(ret).c_str());
    }
 
    return ret;
}
 
int FFmpeg_Base::dict_set_with_check(AVDictionary **pm, const char *key, int64_t value, int flags, const char * filename, bool nodelete) const
{
    if (nodelete && !value)
    {
        return 0;
    }
 
    int ret = av_dict_set_int(pm, key, value, flags);
 
    if (ret < 0)
    {
        Logging::error(filename, "Error setting dictionary option key(%1)='%2' (error '%3').", key, value, ffmpeg_geterror(ret).c_str());
    }
 
    return ret;
}
 
int FFmpeg_Base::opt_set_with_check(void *obj, const char *key, const char *value, int flags, const char * filename) const
{
    int ret = av_opt_set(obj, key, value, flags);
 
    if (ret < 0)
    {
        Logging::error(filename, "Error setting dictionary option key(%1)='%2' (error '%3').", key, value, ffmpeg_geterror(ret).c_str());
    }
 
    return ret;
}
 
void FFmpeg_Base::video_info(bool out_file, const AVFormatContext *format_ctx, const AVStream *stream) const
{
    if (stream != nullptr && stream->codecpar != nullptr)
    {
        int64_t duration = AV_NOPTS_VALUE;
 
        if (stream->duration != AV_NOPTS_VALUE)
        {
            duration = ffmpeg_rescale_q_rnd(stream->duration, stream->time_base);
        }
 
        Logging::debug(out_file ? virtname() : filename(), "Video %1 #%2: %3@%4 [%5]",
                       out_file ? "out" : "in",
                       stream->index,
                       get_codec_name(stream->codecpar->codec_id),
                       format_bitrate((stream->codecpar->bit_rate != 0) ? stream->codecpar->bit_rate : format_ctx->bit_rate).c_str(),
                       format_duration(duration).c_str());
    }
    else
    {
        Logging::debug(out_file ? virtname() : filename(), "Video %1: invalid stream",
                       out_file ? "out" : "in");
    }
}
 
void FFmpeg_Base::audio_info(bool out_file, const AVFormatContext *format_ctx, const AVStream *stream) const
{
    if (stream != nullptr && stream->codecpar != nullptr)
    {
        int64_t duration = AV_NOPTS_VALUE;
 
        if (stream->duration != AV_NOPTS_VALUE)
        {
            duration = ffmpeg_rescale_q_rnd(stream->duration, stream->time_base);
        }
 
        Logging::debug(out_file ? virtname() : filename(), "Audio %1 #2: %3@%4 %5 Channels %6 [%7]",
                       out_file ? "out" : "in",
                       stream->index,
                       get_codec_name(stream->codecpar->codec_id),
                       format_bitrate((stream->codecpar->bit_rate != 0) ? stream->codecpar->bit_rate : format_ctx->bit_rate).c_str(),
                       get_channels(stream->codecpar),
                       format_samplerate(stream->codecpar->sample_rate).c_str(),
                       format_duration(duration).c_str());
    }
    else
    {
        Logging::debug(out_file ? virtname() : filename(), "Audio %1: invalid stream",
                       out_file ? "out" : "in");
    }
}
 
void FFmpeg_Base::subtitle_info(bool out_file, const AVFormatContext * /*format_ctx*/, const AVStream *stream) const
{
    if (stream != nullptr && stream->codecpar != nullptr)
    {
        Logging::debug(out_file ? virtname() : filename(), "Subtitle %1 #%2: %3",
                       out_file ? "out" : "in",
                       stream->index,
                       get_codec_name(stream->codecpar->codec_id));
    }
    else
    {
        Logging::debug(out_file ? virtname() : filename(), "Subtitle %1: invalid stream",
                       out_file ? "out" : "in");
    }
}
 
std::string FFmpeg_Base::get_pix_fmt_name(enum AVPixelFormat pix_fmt)
{
    const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
    return (fmt_name != nullptr ? fmt_name : "none");
}
 
std::string FFmpeg_Base::get_sample_fmt_name(AVSampleFormat sample_fmt)
{
    return av_get_sample_fmt_name(sample_fmt);
}
 
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
std::string FFmpeg_Base::get_channel_layout_name(const AVChannelLayout * ch_layout)
{
    std::array<char, 1024> buffer;
    av_channel_layout_describe(ch_layout, buffer.data(), buffer.size() - 1);
    return buffer.data();
}
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
std::string FFmpeg_Base::get_channel_layout_name(int nb_channels, uint64_t channel_layout)
{
    std::array<char, 1024> buffer;
    av_get_channel_layout_string(buffer.data(), buffer.size() - 1, nb_channels, channel_layout);
    return buffer.data();
}
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
 
uint32_t FFmpeg_Base::pts_to_frame(AVStream* stream, int64_t pts) const
{
    if (pts == AV_NOPTS_VALUE)
    {
        return 0;
    }
    int64_t start_time = (stream->start_time != AV_NOPTS_VALUE) ? stream->start_time : 0;
    AVRational factor = av_mul_q(stream->avg_frame_rate, stream->time_base);
    return static_cast<uint32_t>(av_rescale(pts - start_time, factor.num, factor.den) + 1);
}
 
int64_t FFmpeg_Base::frame_to_pts(AVStream* stream, uint32_t frame_no) const
{
    int64_t start_time = (stream->start_time != AV_NOPTS_VALUE) ? stream->start_time : 0;
    AVRational factor = av_mul_q(stream->avg_frame_rate, stream->time_base);
    return static_cast<uint32_t>(av_rescale(frame_no - 1, factor.den, factor.num) + start_time);
}
 
int FFmpeg_Base::get_channels(const AVCodecParameters *codecpar) const
{
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
    return codecpar->ch_layout.nb_channels;
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
    return codecpar->channels;
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
}
 
void FFmpeg_Base::set_channels(AVCodecParameters *codecpar_out, const AVCodecParameters *codecpar_in) const
{
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
    codecpar_out->ch_layout.nb_channels = codecpar_in->ch_layout.nb_channels;
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
    codecpar_out->channels = codecpar_in->channels;
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
}
 
int FFmpeg_Base::get_channels(const AVCodecContext *codec_ctx) const
{
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
    return codec_ctx->ch_layout.nb_channels;
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
    return codec_ctx->channels;
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
}
 
void FFmpeg_Base::set_channels(AVCodecContext *codec_ctx_out, const AVCodecContext *codec_ctx_in) const
{
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
    codec_ctx_out->ch_layout.nb_channels= codec_ctx_in->ch_layout.nb_channels;
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
    codec_ctx_out->channels = codec_ctx_in->channels;
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
}
 
void FFmpeg_Base::set_channels(AVCodecContext *codec_ctx_out, int channels) const
{
#if LAVU_DEP_OLD_CHANNEL_LAYOUT
    codec_ctx_out->ch_layout.nb_channels = channels;
#else   // !LAVU_DEP_OLD_CHANNEL_LAYOUT
    codec_ctx_out->channels = channels;
#endif  // !LAVU_DEP_OLD_CHANNEL_LAYOUT
}
 
// See...
//
// https://en.wikipedia.org/wiki/SubStation_Alpha
// https://datatracker.ietf.org/doc/html/draft-ietf-cellar-codec-02
// https://fileformats.fandom.com/wiki/SubStation_Alpha
 
int FFmpeg_Base::get_script_info(AVCodecContext *codec_ctx, int play_res_x, int play_res_y, const char *font, int font_size, int primary_color, int secondary_color, int outline_color, int back_color, int bold, int italic, int underline, int border_style, int alignment) const
{
    const char *format =
            "[Script Info]\r\n"                                             //
            "; Script generated by ffmpegfs " FFMPEFS_VERSION "\r\n"        //
            "; https://github.com/nschlia/ffmpegfs\r\n"                     //
            "ScriptType: v4.00+\r\n"                                        //
            "PlayResX: %d\r\n"                                              //
            "PlayResY: %d\r\n"                                              //
            "ScaledBorderAndShadow: yes\r\n"                                //
 
            // Some other tags...
            //"Title: NAME (Language)\r\n"                                  //
            //"Original Script: ???\r\n"                                    //
            //"Script Updated By: version 2.8.01\r\n"                       //
            //"Collisions: Normal\r\n"                                      //
            //"PlayDepth: 0\r\n"                                            //
            //"Timer: 100,0000\r\n"                                         //
            //"Video Aspect Ratio: 0\r\n"                                   //
            //"Video Zoom: 6\r\n"                                           //
            //"Video Position: 0\r\n"                                       //
 
            "\r\n"                                                          //
            "[V4+ Styles]\r\n"                                              //
 
            "Format: "                                                      //
            "Name, "                                                        //
            "Fontname, Fontsize, "                                          //
            "PrimaryColour, SecondaryColour, OutlineColour, BackColour, "   //
            "Bold, Italic, Underline, StrikeOut, "                          //
            "ScaleX, ScaleY, "                                              //
            "Spacing, Angle, "                                              //
            "BorderStyle, Outline, Shadow, "                                //
            "Alignment, MarginL, MarginR, MarginV, "                        //
            "Encoding\r\n"                                                  //
 
            "Style: "                                                       //
            "Default,"                  // Name
            "%s,%d,"                    // Font{name,size}
            "&H%x,&H%x,&H%x,&H%x,"      // {Primary,Secondary,Outline,Back}Colour
            "%d,%d,%d,0,"               // Bold, Italic, Underline, StrikeOut
            "100,100,"                  // Scale{X,Y}
            "0,0,"                      // Spacing, Angle
            "%d,1,0,"                   // BorderStyle, Outline, Shadow
            "%d,10,10,10,"              // Alignment, Margin[LRV]
            "0\r\n"                     // Encoding
            "\r\n"                      //
 
            "[Events]\r\n"              //
            "Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n";
 
    size_t size = static_cast<size_t>(snprintf(nullptr, 0, format,  play_res_x, play_res_y, font, font_size,
                                               primary_color, secondary_color, outline_color, back_color,
                                               -bold, -italic, -underline, border_style, alignment)) + 1; // Extra space for '\0'
 
    codec_ctx->subtitle_header = reinterpret_cast<uint8_t *>(av_malloc(size + 1));
 
    if (codec_ctx->subtitle_header == nullptr)
    {
        return AVERROR(ENOMEM);
    }
 
    snprintf(reinterpret_cast<char *>(codec_ctx->subtitle_header), size, format,
             play_res_x, play_res_y, font, font_size,
             primary_color, secondary_color, outline_color, back_color,
             -bold, -italic, -underline, border_style, alignment);
 
    codec_ctx->subtitle_header_size = static_cast<int>(size);
 
    return 0;
}