AUD_FFMPEGReader.cpp

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * Copyright 2009-2011 Jörg Hermann Müller
 *
 * This file is part of AudaSpace.
 *
 * Audaspace 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 2 of the License, or
 * (at your option) any later version.
 *
 * AudaSpace 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 Audaspace; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

// needed for INT64_C
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif

#include "AUD_FFMPEGReader.h"

extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavformat/avio.h>
#include "ffmpeg_compat.h"
}

int AUD_FFMPEGReader::decode(AVPacket* packet, AUD_Buffer& buffer)
{
    // save packet parameters
    uint8_t *audio_pkg_data = packet->data;
    int audio_pkg_size = packet->size;

    int buf_size = buffer.getSize();
    int buf_pos = 0;

    int read_length, data_size;

    AVPacket tmp_pkt;
    
    av_init_packet(&tmp_pkt);

    // as long as there is still data in the package
    while(audio_pkg_size > 0)
    {
        // resize buffer if needed
        if(buf_size - buf_pos < AVCODEC_MAX_AUDIO_FRAME_SIZE)
        {
            buffer.resize(buf_size + AVCODEC_MAX_AUDIO_FRAME_SIZE, true);
            buf_size += AVCODEC_MAX_AUDIO_FRAME_SIZE;
        }

        // read samples from the packet
        data_size = buf_size - buf_pos;

        tmp_pkt.data = audio_pkg_data;
        tmp_pkt.size = audio_pkg_size;

        read_length = avcodec_decode_audio3(
            m_codecCtx,
            (int16_t*)(((data_t*)buffer.getBuffer()) + buf_pos),
            &data_size, &tmp_pkt);

        // read error, next packet!
        if(read_length < 0)
            break;

        buf_pos += data_size;

        // move packet parameters
        audio_pkg_data += read_length;
        audio_pkg_size -= read_length;
    }

    return buf_pos;
}

static const char* streaminfo_error = "AUD_FFMPEGReader: Stream info couldn't "
                                      "be found.";
static const char* noaudio_error = "AUD_FFMPEGReader: File doesn't include an "
                                   "audio stream.";
static const char* nodecoder_error = "AUD_FFMPEGReader: No decoder found for "
                                     "the audio stream.";
static const char* codecopen_error = "AUD_FFMPEGReader: Codec couldn't be "
                                     "opened.";
static const char* format_error = "AUD_FFMPEGReader: Unsupported sample "
                                  "format.";

void AUD_FFMPEGReader::init()
{
    m_position = 0;
    m_pkgbuf_left = 0;

    if(av_find_stream_info(m_formatCtx)<0)
        AUD_THROW(AUD_ERROR_FFMPEG, streaminfo_error);

    // find audio stream and codec
    m_stream = -1;

    for(unsigned int i = 0; i < m_formatCtx->nb_streams; i++)
    {
        if((m_formatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
            && (m_stream < 0))
        {
            m_stream=i;
            break;
        }
    }

    if(m_stream == -1)
        AUD_THROW(AUD_ERROR_FFMPEG, noaudio_error);

    m_codecCtx = m_formatCtx->streams[m_stream]->codec;

    // get a decoder and open it
    AVCodec *aCodec = avcodec_find_decoder(m_codecCtx->codec_id);
    if(!aCodec)
        AUD_THROW(AUD_ERROR_FFMPEG, nodecoder_error);

    if(avcodec_open(m_codecCtx, aCodec)<0)
        AUD_THROW(AUD_ERROR_FFMPEG, codecopen_error);

    // XXX this prints file information to stdout:
    //dump_format(m_formatCtx, 0, NULL, 0);

    m_specs.channels = (AUD_Channels) m_codecCtx->channels;

    switch(m_codecCtx->sample_fmt)
    {
    case SAMPLE_FMT_U8:
        m_convert = AUD_convert_u8_float;
        m_specs.format = AUD_FORMAT_U8;
        break;
    case SAMPLE_FMT_S16:
        m_convert = AUD_convert_s16_float;
        m_specs.format = AUD_FORMAT_S16;
        break;
    case SAMPLE_FMT_S32:
        m_convert = AUD_convert_s32_float;
        m_specs.format = AUD_FORMAT_S32;
        break;
    case SAMPLE_FMT_FLT:
        m_convert = AUD_convert_copy<float>;
        m_specs.format = AUD_FORMAT_FLOAT32;
        break;
    case SAMPLE_FMT_DBL:
        m_convert = AUD_convert_double_float;
        m_specs.format = AUD_FORMAT_FLOAT64;
        break;
    default:
        AUD_THROW(AUD_ERROR_FFMPEG, format_error);
    }

    m_specs.rate = (AUD_SampleRate) m_codecCtx->sample_rate;
}

static const char* fileopen_error = "AUD_FFMPEGReader: File couldn't be "
                                    "opened.";

AUD_FFMPEGReader::AUD_FFMPEGReader(std::string filename) :
    m_pkgbuf(AVCODEC_MAX_AUDIO_FRAME_SIZE<<1),
    m_formatCtx(NULL),
    m_aviocontext(NULL),
    m_membuf(NULL)
{
    // open file
    if(avformat_open_input(&m_formatCtx, filename.c_str(), NULL, NULL)!=0)
        AUD_THROW(AUD_ERROR_FILE, fileopen_error);

    try
    {
        init();
    }
    catch(AUD_Exception&)
    {
        av_close_input_file(m_formatCtx);
        throw;
    }
}

static const char* streamopen_error = "AUD_FFMPEGReader: Stream couldn't be "
                                      "opened.";

AUD_FFMPEGReader::AUD_FFMPEGReader(AUD_Reference<AUD_Buffer> buffer) :
        m_pkgbuf(AVCODEC_MAX_AUDIO_FRAME_SIZE<<1),
        m_membuffer(buffer),
        m_membufferpos(0)
{
    m_membuf = reinterpret_cast<data_t*>(av_malloc(FF_MIN_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE));

    m_aviocontext = avio_alloc_context(m_membuf, FF_MIN_BUFFER_SIZE, 0, this,
                                       read_packet, NULL, seek_packet);

    if(!m_aviocontext)
    {
        av_free(m_aviocontext);
        AUD_THROW(AUD_ERROR_FILE, fileopen_error);
    }

    m_formatCtx = avformat_alloc_context();
    m_formatCtx->pb = m_aviocontext;
    if(avformat_open_input(&m_formatCtx, "", NULL, NULL)!=0)
    {
        av_free(m_aviocontext);
        AUD_THROW(AUD_ERROR_FILE, streamopen_error);
    }

    try
    {
        init();
    }
    catch(AUD_Exception&)
    {
        av_close_input_stream(m_formatCtx);
        av_free(m_aviocontext);
        throw;
    }
}

AUD_FFMPEGReader::~AUD_FFMPEGReader()
{
    avcodec_close(m_codecCtx);

    if(m_aviocontext)
    {
        av_close_input_stream(m_formatCtx);
        av_free(m_aviocontext);
    }
    else
        av_close_input_file(m_formatCtx);
}

int AUD_FFMPEGReader::read_packet(void* opaque, uint8_t* buf, int buf_size)
{
    AUD_FFMPEGReader* reader = reinterpret_cast<AUD_FFMPEGReader*>(opaque);

    int size = AUD_MIN(buf_size, reader->m_membuffer->getSize() - reader->m_membufferpos);

    if(size < 0)
        return -1;

    memcpy(buf, ((data_t*)reader->m_membuffer->getBuffer()) + reader->m_membufferpos, size);
    reader->m_membufferpos += size;

    return size;
}

int64_t AUD_FFMPEGReader::seek_packet(void* opaque, int64_t offset, int whence)
{
    AUD_FFMPEGReader* reader = reinterpret_cast<AUD_FFMPEGReader*>(opaque);

    switch(whence)
    {
    case SEEK_SET:
        reader->m_membufferpos = 0;
        break;
    case SEEK_END:
        reader->m_membufferpos = reader->m_membuffer->getSize();
        break;
    case AVSEEK_SIZE:
        return reader->m_membuffer->getSize();
    }

    return (reader->m_membufferpos += offset);
}

bool AUD_FFMPEGReader::isSeekable() const
{
    return true;
}

void AUD_FFMPEGReader::seek(int position)
{
    if(position >= 0)
    {
        uint64_t st_time = m_formatCtx->start_time;
        uint64_t seek_pos = ((uint64_t)position) * ((uint64_t)AV_TIME_BASE) / ((uint64_t)m_specs.rate);

        if (seek_pos < 0) {
            seek_pos = 0;
        }

        if (st_time != AV_NOPTS_VALUE) {
            seek_pos += st_time;
        }

        double pts_time_base = 
            av_q2d(m_formatCtx->streams[m_stream]->time_base);
        uint64_t pts_st_time =
            ((st_time != AV_NOPTS_VALUE) ? st_time : 0)
            / pts_time_base / (uint64_t) AV_TIME_BASE;

        // a value < 0 tells us that seeking failed
        if(av_seek_frame(m_formatCtx, -1, seek_pos,
                 AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_ANY) >= 0)
        {
            avcodec_flush_buffers(m_codecCtx);
            m_position = position;

            AVPacket packet;
            bool search = true;

            while(search && av_read_frame(m_formatCtx, &packet) >= 0)
            {
                // is it a frame from the audio stream?
                if(packet.stream_index == m_stream)
                {
                    // decode the package
                    m_pkgbuf_left = decode(&packet, m_pkgbuf);
                    search = false;

                    // check position
                    if(packet.pts != AV_NOPTS_VALUE)
                    {
                        // calculate real position, and read to frame!
                        m_position = (packet.pts - 
                            pts_st_time) * pts_time_base * m_specs.rate;

                        if(m_position < position)
                        {
                            // read until we're at the right position
                            int length = AUD_DEFAULT_BUFFER_SIZE;
                            AUD_Buffer buffer(length * AUD_SAMPLE_SIZE(m_specs));
                            bool eos;
                            for(int len = position - m_position;
                                length == AUD_DEFAULT_BUFFER_SIZE;
                                len -= AUD_DEFAULT_BUFFER_SIZE)
                            {
                                if(len < AUD_DEFAULT_BUFFER_SIZE)
                                    length = len;
                                read(length, eos, buffer.getBuffer());
                            }
                        }
                    }
                }
                av_free_packet(&packet);
            }
        }
        else
        {
            fprintf(stderr, "seeking failed!\n");
            // Seeking failed, do nothing.
        }
    }
}

int AUD_FFMPEGReader::getLength() const
{
    // return approximated remaning size
    return (int)((m_formatCtx->duration * m_codecCtx->sample_rate)
                 / AV_TIME_BASE)-m_position;
}

int AUD_FFMPEGReader::getPosition() const
{
    return m_position;
}

AUD_Specs AUD_FFMPEGReader::getSpecs() const
{
    return m_specs.specs;
}

void AUD_FFMPEGReader::read(int& length, bool& eos, sample_t* buffer)
{
    // read packages and decode them
    AVPacket packet;
    int data_size = 0;
    int pkgbuf_pos;
    int left = length;
    int sample_size = AUD_DEVICE_SAMPLE_SIZE(m_specs);

    sample_t* buf = buffer;
    pkgbuf_pos = m_pkgbuf_left;
    m_pkgbuf_left = 0;

    // there may still be data in the buffer from the last call
    if(pkgbuf_pos > 0)
    {
        data_size = AUD_MIN(pkgbuf_pos, left * sample_size);
        m_convert((data_t*) buf, (data_t*) m_pkgbuf.getBuffer(),
                  data_size / AUD_FORMAT_SIZE(m_specs.format));
        buf += data_size / AUD_FORMAT_SIZE(m_specs.format);
        left -= data_size/sample_size;
    }

    // for each frame read as long as there isn't enough data already
    while((left > 0) && (av_read_frame(m_formatCtx, &packet) >= 0))
    {
        // is it a frame from the audio stream?
        if(packet.stream_index == m_stream)
        {
            // decode the package
            pkgbuf_pos = decode(&packet, m_pkgbuf);

            // copy to output buffer
            data_size = AUD_MIN(pkgbuf_pos, left * sample_size);
            m_convert((data_t*) buf, (data_t*) m_pkgbuf.getBuffer(),
                      data_size / AUD_FORMAT_SIZE(m_specs.format));
            buf += data_size / AUD_FORMAT_SIZE(m_specs.format);
            left -= data_size/sample_size;
        }
        av_free_packet(&packet);
    }
    // read more data than necessary?
    if(pkgbuf_pos > data_size)
    {
        m_pkgbuf_left = pkgbuf_pos-data_size;
        memmove(m_pkgbuf.getBuffer(),
                ((data_t*)m_pkgbuf.getBuffer())+data_size,
                pkgbuf_pos-data_size);
    }

    if((eos = (left > 0)))
        length -= left;

    m_position += length;
}