root/branches/perian-1.0/ff_private.c

/*****************************************************************************
*
*  Avi Import Component Private Functions
*
*  Copyright(C) 2006 Christoph Naegeli <chn1@mac.com>
*
*  This library is free software; you can redistribute it and/or
*  modify it under the terms of the GNU Lesser General Public
*  License as published by the Free Software Foundation; either
*  version 2.1 of the License, or (at your option) any later version.
*  
*  This library 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
*  Lesser General Public License for more details.
*  
*  You should have received a copy of the GNU Lesser General Public
*  License along with this library; if not, write to the Free Software
*  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*
****************************************************************************/

#include "ff_private.h"
#include "avcodec.h"
#include "mpegaudio.h"
#include "allformats.h"
#include "Codecprintf.h"
#include "CommonUtils.h"
#include "CodecIDs.h"

#include <CoreServices/CoreServices.h>
#include <AudioToolbox/AudioToolbox.h>
#include <QuickTime/QuickTime.h>

#include "bitstream_info.h"
#include "MatroskaCodecIDs.h"

/* This routine checks if the system requirements are fullfilled */
ComponentResult check_system()
{
        ComponentResult result;
        long systemVersion;
        
        result = Gestalt(gestaltSystemVersion, &systemVersion);
        require_noerr(result,bail);
        
        /* Make sure we have at least 10.4 installed...*/
        if(systemVersion < 0x00001040)
                result = -1;
        
bail:
                return result;
} /* check_system() */

/* This routine does register the ffmpeg parsers which would normally
 * be registred through the normal initialization process */
void register_parsers()
{
        /* Do we need more parsers here? */
//    av_register_codec_parser(&mpegaudio_parser);
//      av_register_codec_parser(&ac3_parser);
} /* register_parsers() */


/* This function prepares the target Track to receivve the movie data,
 * it is called if QT has asked an import operation which should just
 * load this track. After success, *outmap points to a valid stream maping
 * Return values:
 *        0: ok
 *      < 0: couldn't find a matching track
 */
int prepare_track(ff_global_ptr storage, Track targetTrack, Handle dataRef, OSType dataRefType)
{
        int j;
        AVStream *st = NULL;
        AVStream *outstr = NULL;
        Media media;
        NCStream *map = NULL;
        AVFormatContext *ic = storage->format_context;
        
        /* If the track has already a media, return an err */
        media = GetTrackMedia(targetTrack);
        if(media) goto err;
        
        /* Search the AVFormatContext for a video stream */
        for(j = 0; j < ic->nb_streams && !outstr; j++) {
                st = ic->streams[j];
                if(st->codec->codec_type == CODEC_TYPE_VIDEO)
                        outstr = st;
        }
        /* Search the AVFormatContext for an audio stream (no video stream exists) */
        for(j = 0; j < ic->nb_streams && !outstr; j++) {
                st = ic->streams[j];
                if(st->codec->codec_type == CODEC_TYPE_AUDIO)
                        outstr = st;
        }
        /* Still no stream, then err */
        if(!outstr) goto err;
        
        /* prepare the stream map & initialize*/
        map = av_mallocz(sizeof(NCStream));
        map->index = st->index;
        map->str = outstr;
        
        if(st->codec->codec_type == CODEC_TYPE_VIDEO)
                initialize_video_map(map, targetTrack, dataRef, dataRefType, storage->firstFrames + st->index);
        else if(st->codec->codec_type == CODEC_TYPE_AUDIO)
                initialize_audio_map(map, targetTrack, dataRef, dataRefType, storage->firstFrames + st->index);
        
        /* return the map */
        storage->stream_map = map;
        
        return 0;
err:
                if(map)
                        av_free(map);
        return -1;
} /* prepare_track() */

/* Initializes the map & targetTrack to receive video data */
void initialize_video_map(NCStream *map, Track targetTrack, Handle dataRef, OSType dataRefType, AVPacket *firstFrame)
{
        Media media;
        ImageDescriptionHandle imgHdl;
        Handle imgDescExt = NULL;
        AVCodecContext *codec;
        double num,den;
        
        codec = map->str->codec;
        
        map->base = map->str->time_base;
        if(map->base.den > 100000) {
                /* if that's the case, then we probably ran out of timevalues!
                * a timescale of 100000 allows a movie duration of 5-6 hours
                * so I think this will be enough */
                den = map->base.den;
                num = map->base.num;
                
                /* we use the following approach ##.### frames per second.
                        * afterwards rounding */
                den = den / num * 1000.0;
                map->base.num = 1000;
                map->base.den = round(den);
        }
        
        media = NewTrackMedia(targetTrack, VideoMediaType, map->base.den, dataRef, dataRefType);
        map->media = media;
        
        /* Create the Image Description Handle */
        imgHdl = (ImageDescriptionHandle)NewHandleClear(sizeof(ImageDescription));
        (*imgHdl)->idSize = sizeof(ImageDescription);
        
        if (codec->codec_tag)
                (*imgHdl)->cType = BSWAP(codec->codec_tag);
        else
                // need to lookup the fourcc from the codec_id
                (*imgHdl)->cType = map_video_codec_to_mov_tag(codec->codec_id);
//      FourCCprintf("fourcc: ", (*imgHdl)->cType);
        
        (*imgHdl)->temporalQuality = codecMaxQuality;
        (*imgHdl)->spatialQuality = codecMaxQuality;
        (*imgHdl)->width = codec->width;
        (*imgHdl)->height = codec->height;
        (*imgHdl)->hRes = 72 << 16;
        (*imgHdl)->vRes = 72 << 16;
        (*imgHdl)->depth = codec->bits_per_sample;
        (*imgHdl)->clutID = -1; // no color lookup table...
        
        /* Create the strf image description extension (see AVI's BITMAPINFOHEADER) */
        imgDescExt = create_strf_ext(codec);
        if (imgDescExt) {
                AddImageDescriptionExtension(imgHdl, imgDescExt, 'strf');
                DisposeHandle(imgDescExt);
        }
        
        map->sampleHdl = (SampleDescriptionHandle)imgHdl;
        
} /* initialize_video_map() */

/* Initializes the map & targetTrack to receive audio data */
void initialize_audio_map(NCStream *map, Track targetTrack, Handle dataRef, OSType dataRefType, AVPacket *firstFrame)
{
        Media media;
        SoundDescriptionHandle sndHdl;
        AudioStreamBasicDescription asbd;
        AVCodecContext *codec;
        UInt32 ioSize;
        OSStatus err;
        
        uint8_t *cookie = NULL;
        int cookieSize = 0;
        
        codec = map->str->codec;
        map->base = map->str->time_base;
        
        media = NewTrackMedia(targetTrack, SoundMediaType, codec->sample_rate, dataRef, dataRefType);
        
        map->media = media;
        
        memset(&asbd,0,sizeof(asbd));
        map_avi_to_mov_tag(codec->codec_id, &asbd, map);
        if(asbd.mFormatID == 0) /* no know codec, use the ms tag */
                asbd.mFormatID = 'ms\0\0' + codec->codec_tag; /* the number is stored in the last byte => big endian */
        
        /* Ask the AudioToolbox about vbr of the codec */
        ioSize = sizeof(UInt32);
        AudioFormatGetProperty(kAudioFormatProperty_FormatIsVBR, sizeof(AudioStreamBasicDescription), &asbd, &ioSize, &map->vbr);
        
        /* ask the toolbox about more information */
        ioSize = sizeof(AudioStreamBasicDescription);
        AudioFormatGetProperty(kAudioFormatProperty_FormatInfo, 0, NULL, &ioSize, &asbd);
        
        /* Set some fields of the AudioStreamBasicDescription. Then ask the AudioToolbox
                * to fill as much as possible before creating the SoundDescriptionHandle */
        asbd.mSampleRate = codec->sample_rate;
        asbd.mChannelsPerFrame = codec->channels;
        if(!map->vbr) /* This works for all the tested codecs. but is there any better way? */
                asbd.mBytesPerPacket = codec->block_align; /* this is tested for alaw/mulaw/msadpcm */
        asbd.mFramesPerPacket = codec->frame_size; /* works for mp3, all other codecs this is 0 anyway */
        asbd.mBitsPerChannel = codec->bits_per_sample;
        
        // this probably isn't quite right; FLV doesn't set frame_size or block_align, 
        // but we need > 0 frames per packet or Apple's mp3 decoder won't work
        if (asbd.mBytesPerPacket == 0 && asbd.mFramesPerPacket == 0)
                asbd.mFramesPerPacket = 1;
        
        // if we don't have mBytesPerPacket, we can't import as CBR. Probably should be VBR, and the codec
        // either lied about kAudioFormatProperty_FormatIsVBR or isn't present
        if (asbd.mBytesPerPacket == 0)
                map->vbr = 1;
        
        /* If we have vbr audio, the media scale most likely has to be set to the time_base denumerator */
        if(map->vbr) {
                /* if we have mFramesPerPacket, set mBytesPerPacket to 0 as this can cause
                * errors if set incorrectly. But in vbr, we just need the mFramesPerPacket
                * value */
                if(asbd.mFramesPerPacket)
                        asbd.mBytesPerPacket = 0;
                SetMediaTimeScale(media, map->str->time_base.den);
        }
        
        /* FIXME. in the MSADPCM codec, we get a wrong mFramesPerPacket entry because
                * of the difference in the sample_rate and the time_base denumerator. So we
                * recalculate here the mFramesPerPacket entry */
        if(asbd.mBytesPerPacket) {
                /* For calculation, lets assume a packet duration of 1, use ioSize as tmp storage */
                ioSize = map->str->time_base.num * codec->sample_rate / map->str->time_base.den;
                /* downscale to correct bytes_per_packet */
                asbd.mFramesPerPacket = ioSize * asbd.mBytesPerPacket / codec->block_align;
        }
        
        AudioChannelLayout acl;
        int aclSize = 0;  //Set this if you intend to use it
        memset(&acl, 0, sizeof(AudioChannelLayout));

        /* We have to parse the format */
        int useDefault = 1;
        if(asbd.mFormatID == kAudioFormatAC3 || asbd.mFormatID == 'ms \0')
        {
                if(parse_ac3_bitstream(&asbd, &acl, firstFrame->data, firstFrame->size))
                {
                        useDefault = 0;
                        aclSize = sizeof(AudioChannelLayout);
                }
        }
        if(useDefault && asbd.mChannelsPerFrame > 2)
        {
                acl = GetDefaultChannelLayout(&asbd);
                aclSize = sizeof(AudioChannelLayout);
        }
        err = QTSoundDescriptionCreate(&asbd, aclSize == 0 ? NULL : &acl, aclSize, NULL, 0, kQTSoundDescriptionKind_Movie_LowestPossibleVersion, &sndHdl);
        if(err) fprintf(stderr, "AVI IMPORTER: Error creating the sound description\n");
        
        /* Create the magic cookie */
        cookie = create_cookie(codec, &cookieSize, asbd.mFormatID);
        if(cookie) {
                err = QTSoundDescriptionSetProperty(sndHdl, kQTPropertyClass_SoundDescription, kQTSoundDescriptionPropertyID_MagicCookie,
                                                                                        cookieSize, cookie);
                if(err) fprintf(stderr, "AVI IMPORTER: Error appending the magic cookie to the sound description\n");
                av_free(cookie);
        }
        
        map->sampleHdl = (SampleDescriptionHandle)sndHdl;
        map->asbd = asbd;
} /* initialize_audio_map() */

OSType map_video_codec_to_mov_tag(enum CodecID codec_id)
{
        switch(codec_id) {
                case CODEC_ID_FLV1:
                        return 'FLV1';
                case CODEC_ID_VP6F:
                        return 'VP6F';
                case CODEC_ID_FLASHSV:
                        return 'FSV1';
        }
        return 0;
}

/* maps the codec_id tag of libavformat to a constant the AudioToolbox can work with */
void map_avi_to_mov_tag(enum CodecID codec_id, AudioStreamBasicDescription *asbd, NCStream *map)
{
        switch(codec_id) {
                case CODEC_ID_MP2:
                        asbd->mFormatID = kAudioFormatMPEGLayer2;
                        break;
                case CODEC_ID_MP3:
                        asbd->mFormatID = kAudioFormatMPEGLayer3;
                        break;
                case CODEC_ID_AC3:
                        asbd->mFormatID = kAudioFormatAC3;
                        map->vbr = 1;
                        break;
                case CODEC_ID_PCM_S16LE:
                        asbd->mFormatID = kAudioFormatLinearPCM;
                        asbd->mFormatFlags = kLinearPCMFormatFlagIsSignedInteger;
                        break;
                case CODEC_ID_PCM_U8:
                        asbd->mFormatID = kAudioFormatLinearPCM;
                        asbd->mFormatFlags = kLinearPCMFormatFlagIsBigEndian;
                        break;
                case CODEC_ID_PCM_ALAW:
                        asbd->mFormatID = kAudioFormatALaw;
                        break;
                case CODEC_ID_PCM_MULAW:
                        asbd->mFormatID = kAudioFormatULaw;
                        break;
                case CODEC_ID_ADPCM_MS:
                        asbd->mFormatID = kMicrosoftADPCMFormat;
                        break;
                case CODEC_ID_AAC:
                        asbd->mFormatID = kAudioFormatMPEG4AAC;
                        break;
                case CODEC_ID_VORBIS:
                        asbd->mFormatID = 'OggV';
                        break;
                case CODEC_ID_DTS:
                        asbd->mFormatID = kAudioFormatDTS;
                        map->vbr = 1;
                        break;
                case CODEC_ID_ADPCM_SWF:
                        asbd->mFormatID = kAudioFormatFlashADPCM;
                        break;
                default:
                        break;
        }
} /* map_avi_to_mov_tag() */

/* This function creates a magic cookie basec on the codec parameter and formatID
 * Return value: a pointer to a magic cookie which has to be av_free()'d
 * in cookieSize, the size of the magic cookie is returned to the caller */
uint8_t *create_cookie(AVCodecContext *codec, int *cookieSize, UInt32 formatID)
{
        uint8_t *result = NULL;
        uint8_t *ptr;
        AudioFormatAtom formatAtom;
        AudioTerminatorAtom termAtom;
        long waveSize;
        uint8_t *waveAtom = NULL;
        int size = 0;
        
        /* Do we need an endia atom, too? */
        
        /* initialize the user Atom
                * 8 bytes                       for the atom size & atom type
                * 18 bytes                      for the already extracted part, see wav.c in the ffmpeg project
                * extradata_size        for the data still stored in the AVCodecContext structure */
        waveSize = 18 + codec->extradata_size + 8;
        waveAtom = av_malloc(waveSize);
        
        /* now construct the wave atom */
        /* QT Atoms are big endian, I think but the WAVE data should be little endian */
        ptr = write_int32(waveAtom, EndianS32_NtoB(waveSize));
        ptr = write_int32(ptr, EndianS32_NtoB(formatID));
        ptr = write_int16(ptr, EndianS16_NtoL(codec->codec_tag));
        ptr = write_int16(ptr, EndianS16_NtoL(codec->channels));
        ptr = write_int32(ptr, EndianS32_NtoL(codec->sample_rate));
        ptr = write_int32(ptr, EndianS32_NtoL(codec->bit_rate / 8));
        ptr = write_int16(ptr, EndianS16_NtoL(codec->block_align));
        ptr = write_int16(ptr, EndianS16_NtoL(codec->bits_per_sample));
        ptr = write_int16(ptr, EndianS16_NtoL(codec->extradata_size));
        /* now the remaining stuff */
        ptr = write_data(ptr, codec->extradata, codec->extradata_size);
        
        /* Calculate the size of the cookie */
        size  = sizeof(formatAtom) + sizeof(termAtom) + waveSize;
        
        /* Audio Format Atom */
        formatAtom.size = EndianS32_NtoB(sizeof(AudioFormatAtom));
        formatAtom.atomType = EndianS32_NtoB(kAudioFormatAtomType);
        formatAtom.format = EndianS32_NtoB(formatID);
        
        /* Terminator Atom */
        termAtom.atomType = EndianS32_NtoB(kAudioTerminatorAtomType);
        termAtom.size = EndianS32_NtoB(sizeof(AudioTerminatorAtom));
        
        result = av_malloc(size);
        
        /* use ptr to write to the result */
        ptr = result;
        
        /* format atom */
        ptr = write_data(ptr, (uint8_t*)&formatAtom, sizeof(formatAtom));
        ptr = write_data(ptr, waveAtom, waveSize);
        ptr = write_data(ptr, (uint8_t*)&termAtom, sizeof(termAtom));
        
bail:
                *cookieSize = size;
        if(waveAtom)
                av_free(waveAtom);
        return result;
} /* create_cookie() */

/* This function creates an image description extension that some codecs need to be able 
 * to decode properly, a copy of the strf (BITMAPINFOHEADER) chunk in the avi.
 * Return value: a handle to an image description extension which has to be DisposeHandle()'d
 * in cookieSize, the size of the image description extension is returned to the caller */
Handle create_strf_ext(AVCodecContext *codec)
{
        Handle result = NULL;
        uint8_t *ptr;
        long size;
        
        /* initialize the extension
                * 40 bytes                      for the BITMAPINFOHEADER stucture, see avienc.c in the ffmpeg project
                * extradata_size        for the data still stored in the AVCodecContext structure */
        size = 40 + codec->extradata_size;
        result = NewHandle(size);
        if (result == NULL)
                goto bail;
        
        /* construct the BITMAPINFOHEADER structure */
        /* QT Atoms are big endian, but the STRF atom should be little endian */
        ptr = write_int32((uint8_t *)*result, EndianS32_NtoL(size)); /* size */
        ptr = write_int32(ptr, EndianS32_NtoL(codec->width));
        ptr = write_int32(ptr, EndianS32_NtoL(codec->height));
        ptr = write_int16(ptr, EndianS16_NtoL(1)); /* planes */
        
        ptr = write_int16(ptr, EndianS16_NtoL(codec->bits_per_sample ? codec->bits_per_sample : 24)); /* depth */
        /* compression type */
        ptr = write_int32(ptr, EndianS32_NtoL(codec->codec_tag));
        ptr = write_int32(ptr, EndianS32_NtoL(codec->width * codec->height * 3));
        ptr = write_int32(ptr, EndianS32_NtoL(0));
        ptr = write_int32(ptr, EndianS32_NtoL(0));
        ptr = write_int32(ptr, EndianS32_NtoL(0));
        ptr = write_int32(ptr, EndianS32_NtoL(0));
        
        /* now the remaining stuff */
        ptr = write_data(ptr, codec->extradata, codec->extradata_size);
        
        if (codec->extradata_size & 1) {
                uint8_t zero = 0;
                ptr = write_data(ptr, &zero, 1);
        }
        
bail:
        return result;
} /* create_extension() */

/* Add the meta data that lavf exposes to the movie */
static void add_metadata(AVFormatContext *ic, Movie theMovie)
{
    QTMetaDataRef movie_metadata;
    OSType key, err;
    
    err = QTCopyMovieMetaData(theMovie, &movie_metadata);
    if (err) return;
    
        if (strlen(ic->title)) {
                key = kQTMetaDataCommonKeyDisplayName;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->title, strlen(ic->title), kQTMetaDataTypeUTF8, NULL);
        }
        if (strlen(ic->author)) {
                key = kQTMetaDataCommonKeyAuthor;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->author, strlen(ic->author), kQTMetaDataTypeUTF8, NULL);
        }
        if (strlen(ic->copyright)) {
                key = kQTMetaDataCommonKeyCopyright;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->copyright, strlen(ic->copyright), kQTMetaDataTypeUTF8, NULL);
        }
        if (strlen(ic->comment)) {
                key = kQTMetaDataCommonKeyComment;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->comment, strlen(ic->comment), kQTMetaDataTypeUTF8, NULL);
        }
        if (strlen(ic->album)) {
                key = kQTMetaDataCommonKeyComment;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->album, strlen(ic->album), kQTMetaDataTypeUTF8, NULL);
        }
        if (strlen(ic->genre)) {
                key = kQTMetaDataCommonKeyGenre;
                QTMetaDataAddItem(movie_metadata, kQTMetaDataStorageFormatQuickTime, kQTMetaDataKeyFormatCommon, 
                                  (UInt8 *)&key, sizeof(key), (UInt8 *)ic->genre, strlen(ic->genre), kQTMetaDataTypeUTF8, NULL);
        }
    QTMetaDataRelease(movie_metadata);
}

/* This function prepares the movie to receivve the movie data,
 * After success, *out_map points to a valid stream maping
 * Return values:
 *        0: ok
 */
int prepare_movie(ff_global_ptr storage, Movie theMovie, Handle dataRef, OSType dataRefType)
{
        int j;
        AVStream *st;
        NCStream *map;
        Track track;
        Track first_audio_track = NULL;
        AVFormatContext *ic = storage->format_context;
        
        /* make the stream map structure */
        map = av_mallocz(ic->nb_streams * sizeof(NCStream));
        
        for(j = 0; j < ic->nb_streams; j++) {
                
                st = ic->streams[j];
                map[j].index = st->index;
                map[j].str = st;
                map[j].duration = -1;
                
                if(st->codec->codec_type == CODEC_TYPE_VIDEO) {
                        track = NewMovieTrack(theMovie, st->codec->width << 16, st->codec->height << 16, kNoVolume);
                        initialize_video_map(&map[j], track, dataRef, dataRefType, storage->firstFrames + j);
                } else if (st->codec->codec_type == CODEC_TYPE_AUDIO) {
                        track = NewMovieTrack(theMovie, 0, 0, kFullVolume);
                        initialize_audio_map(&map[j], track, dataRef, dataRefType, storage->firstFrames + j);
                        
                        if (first_audio_track == NULL)
                                first_audio_track = track;
                        else
                                SetTrackAlternate(track, first_audio_track);
                }
        }
        
    add_metadata(ic, theMovie);
    
        storage->stream_map = map;
        
        return 0;
} /* prepare_movie() */

int determine_header_offset(ff_global_ptr storage) {
        AVFormatContext *formatContext;
        AVPacket packet;
        int result, i;
        
        formatContext = storage->format_context;
        result = noErr;
        storage->header_offset = 0;
        
        /* Seek backwards to get a manually read packet for file offset */
        if(formatContext->streams[0]->index_entries == NULL || storage->componentType == 'FLV ')
        {
                if (IS_AVI(storage->componentType))
                        //Try to seek to the first frame; don't care if it fails
                        // Is this really needed for AVIs w/out an index? It seems to work fine without, 
                        // and it seems that with it the first frame is skipped.
                        av_seek_frame(formatContext, -1, 0, 0);
                storage->header_offset = 0;
        }
        else
        {
                int streamsRead = 0;
                AVStream *st;
                
                result = av_seek_frame(formatContext, -1, 0, 0);
                if(result < 0) goto bail;
                
                av_read_frame(formatContext, &packet);
                st = formatContext->streams[packet.stream_index];
                
                /* read_packet will give the first decodable packet. However, that isn't necessarily
                        the first entry in the index, so look for an entry with a matching size. */
                for (i = 0; i < st->nb_index_entries; i++) {
                        if (packet.dts == st->index_entries[i].timestamp) {
                                storage->header_offset = packet.pos - st->index_entries[i].pos;
                                break;
                        }
                }
                while(streamsRead < formatContext->nb_streams)
                {
                        int streamIndex = packet.stream_index;
                        if(storage->firstFrames[streamIndex].size == 0)
                        {
                                memcpy(storage->firstFrames + streamIndex, &packet, sizeof(AVPacket));
                                streamsRead++;
                                if(streamsRead == formatContext->nb_streams)
                                        break;
                        }
                        else
                                av_free_packet(&packet);
                        formatContext->iformat->read_packet(formatContext, &packet);
                }
                
                // seek back to the beginning, otherwise av_read_frame-based decoding will skip a few packets.
                av_seek_frame(formatContext, -1, 0, 0);
        }
                
bail:
        return(result);
}

/* This function imports the avi represented by the AVFormatContext to the movie media represented
 * in the map function. The aviheader_offset is used to calculate the packet offset from the
 * beginning of the file. It returns whether it was successful or not (i.e. whether the file had an index) */
int import_using_index(ff_global_ptr storage, int *hadIndex, TimeValue *addedDuration) {
        int j, k, l;
        NCStream *map;
        NCStream *ncstr;
        AVFormatContext *ic;
        AVStream *stream;
        AVCodecContext *codec;
        SampleReference64Ptr sampleRec;
        int64_t header_offset, offset, duration;
        short flags;
        int sampleNum;
        ComponentResult result = noErr;
        
        map = storage->stream_map;
        ic = storage->format_context;
        header_offset = storage->header_offset;

        *hadIndex = 0;
        
        // AVIs without an index currently add one entry to the index; assume that
        // such a small index means that we should idle import instead. It shouldn't 
        // take much longer if the index really is this small anyways.
        for (j = 0; j < ic->nb_streams; j++) {
                if (map[j].str->nb_index_entries <= 1)
                        goto bail;
        }
        
        //FLVs have unusable indexes, so don't even bother.
        if(storage->componentType == 'FLV ')
                goto bail;
        
        /* process each stream in ic */
        for(j = 0; j < ic->nb_streams; j++) {
                ncstr = &map[j];
                stream = ncstr->str;
                codec = stream->codec;
                
                /* no stream we can read */
                if(!ncstr->media)
                        continue;
                
                /* no index, we might as well skip */
                if(stream->nb_index_entries == 0)
                        continue;
                
                sampleNum = 0;
                ncstr->sampleTable = calloc(stream->nb_index_entries, sizeof(SampleReference64Record));
                        
                /* now parse the index entries */
                for(k = 0; k < stream->nb_index_entries; k++) {
                        
                        /* file offset */
                        offset = header_offset + stream->index_entries[k].pos;
                        
                        /* flags */
                        flags = 0;
                        if((stream->index_entries[k].flags & AVINDEX_KEYFRAME) == 0)
                                flags |= mediaSampleNotSync;
                        
                        sampleRec = &ncstr->sampleTable[sampleNum++];
                        
                        /* set as many fields in sampleRec as possible */
                        sampleRec->dataOffset.hi = offset >> 32;
                        sampleRec->dataOffset.lo = (uint32_t)offset;
                        sampleRec->dataSize = stream->index_entries[k].size;
                        sampleRec->sampleFlags = flags;
                        
                        /* some samples have a data_size of zero. if that's the case, ignore them
                                * they seem to be used to stretch the frame duration & are already handled
                                * by the previous pkt */
                        if(sampleRec->dataSize <= 0) {
                                sampleNum--;
                                continue;
                        }
                        
                        /* switch for the remaining fields */
                        if(codec->codec_type == CODEC_TYPE_VIDEO) {
                                
                                /* Calculate the frame duration */
                                duration = 1;
                                for(l = k+1; l < stream->nb_index_entries; l++) {
                                        if(stream->index_entries[l].size > 0)
                                                break;
                                        duration++;
                                }
                                
                                sampleRec->durationPerSample = map->base.num * duration;
                                sampleRec->numberOfSamples = 1;
                        }
                        else if(codec->codec_type == CODEC_TYPE_AUDIO) {
                                
                                /* FIXME: check if that's really the right thing to do here */
                                if(ncstr->vbr) {
                                        sampleRec->numberOfSamples = 1;
                                        
                                        if (k + 1 < stream->nb_index_entries)
                                                sampleRec->durationPerSample = (stream->index_entries[k+1].timestamp - stream->index_entries[k].timestamp) * ncstr->base.num;
                                        else if (sampleNum - 2 >= 0)
                                                // if we're at the last index entry, use the duration of the previous sample
                                                // FIXME: this probably could be better
                                                sampleRec->durationPerSample = ncstr->sampleTable[sampleNum-2].durationPerSample;
                                        
                                } else {
                                        sampleRec->durationPerSample = 1;
                                        sampleRec->numberOfSamples = (stream->index_entries[k].size * ncstr->asbd.mFramesPerPacket) / ncstr->asbd.mBytesPerPacket;
                                }
                        }
                }
                if(sampleNum != 0)
                {
                        /* Add all of the samples to the media */
                        AddMediaSampleReferences64(ncstr->media, ncstr->sampleHdl, sampleNum, ncstr->sampleTable, NULL);
                        free(ncstr->sampleTable);                       

                        /* The index is both present and not empty */
                        *hadIndex = 1;
                }
        }
        
        if(*hadIndex == 0)
                //No index, the remainder of this function will fail.
                goto bail;
        
        // insert media and set addedDuration;
        for(j = 0; j < storage->map_count && result == noErr; j++) {
                Media media = storage->stream_map[j].media;
                if(media) {
                        Track track;
                        TimeRecord time;
                        TimeValue mediaDuration;
                        TimeScale mediaTimeScale;
                        TimeScale movieTimeScale;

                        mediaDuration = GetMediaDuration(media);
                        mediaTimeScale = GetMediaTimeScale(media);
                        movieTimeScale = GetMovieTimeScale(storage->movie);
                        
                        /* we could handle this stream.
                        * convert the atTime parameter to track scale.
                        * FIXME: check if that's correct */
                        time.value.hi = 0;
                        time.value.lo = storage->atTime;
                        time.scale = movieTimeScale;
                        time.base = NULL;
                        ConvertTimeScale(&time, mediaTimeScale);
                        
                        track = GetMediaTrack(media);
                        result = InsertMediaIntoTrack(track, time.value.lo, 0, mediaDuration, fixed1);

                        if(result != noErr)
                                goto bail;
                        
                        time.value.hi = 0;
                        time.value.lo = mediaDuration;
                        time.scale = mediaTimeScale;
                        time.base = NULL;
                        ConvertTimeScale(&time, movieTimeScale);
                        
                        if(time.value.lo > *addedDuration)
                                *addedDuration = time.value.lo;
                }
        }
        
        storage->loadedTime = *addedDuration;
        
bail:
        return result;
} /* import_using_index() */

/* Import function for movies that lack an index.
 * Supports progressive importing, but will not idle if maxFrames == 0.
 */
ComponentResult import_with_idle(ff_global_ptr storage, long inFlags, long *outFlags, int minFrames, int maxFrames, bool addSamples) {
        SampleReference64Record sampleRec;
        DataHandler dataHandler;
        AVFormatContext *formatContext;
        AVCodecContext *codecContext;
        AVStream *stream;
        AVPacket packet;
        NCStream *ncstream;
        ComponentResult dataResult; //used for data handler operations that can fail.
        ComponentResult result;
        TimeValue minLoadedTime;
        int64_t availableSize, margin;
        long idling;
        int readResult, framesProcessed, i;
        short flags;
        
        dataHandler = storage->dataHandler;
        formatContext = storage->format_context;
        dataResult = noErr;
        result = noErr;
        minLoadedTime = -1;
        availableSize = 0;
        margin = 0;
        idling = (inFlags & movieImportWithIdle);
        framesProcessed = 0;
                
        if(idling) {
                //get the size of immediately available data
                if(storage->dataHandlerSupportsWideOffsets) {
                        wide wideSize;
                        
                        dataResult = DataHGetAvailableFileSize64(storage->dataHandler, &wideSize);
                        if(dataResult == noErr) availableSize = ((int64_t)wideSize.hi << 32) + wideSize.lo;
                } else {
                        long longSize;
                        
                        dataResult = DataHGetAvailableFileSize(storage->dataHandler, &longSize);
                        if(dataResult == noErr) availableSize = longSize;
                }
        }
        
        // record stream durations before we add any samples so that we know what to tell InsertMediaIntoTrack later
        for(i = 0; i < storage->map_count; i++) {
                ncstream = &storage->stream_map[i];
                Media media = ncstream->media;
                
                if(media && ncstream->duration == -1)
                        ncstream->duration = GetMediaDuration(media);
        }
        
        while((readResult = av_read_frame(formatContext, &packet)) == 0) {              
                ncstream = &storage->stream_map[packet.stream_index];
                stream = ncstream->str;
                codecContext = stream->codec;
                flags = 0;
                
                if((packet.flags & PKT_FLAG_KEY) == 0)
                        flags |= mediaSampleNotSync;
                
                memset(&sampleRec, 0, sizeof(sampleRec));
                sampleRec.dataOffset.hi = packet.pos >> 32;
                sampleRec.dataOffset.lo = (uint32_t)packet.pos;
                sampleRec.dataSize = packet.size;
                sampleRec.sampleFlags = flags;
                
                if(packet.size > storage->largestPacketSize)
                        storage->largestPacketSize = packet.size;
                
                if(sampleRec.dataSize <= 0)
                        continue;
                
                if(codecContext->codec_type == CODEC_TYPE_AUDIO && !ncstream->vbr)
                        sampleRec.numberOfSamples = (packet.size * ncstream->asbd.mFramesPerPacket) / ncstream->asbd.mBytesPerPacket;
                else
                        sampleRec.numberOfSamples = 1; //packet.duration;
                
                //add any samples waiting to be added
                if(ncstream->lastSample.numberOfSamples > 0) {
                        //calculate the duration of the sample before adding it
                        ncstream->lastSample.durationPerSample = (packet.pts - ncstream->lastpts) * ncstream->base.num;
                        
                        AddMediaSampleReferences64(ncstream->media, ncstream->sampleHdl, 1, &ncstream->lastSample, NULL);
                }
                
                if(packet.duration == 0) {
                        //no duration, we'll have to wait for the next packet to calculate it
                        // keep the duration of the last sample, so we can use it if it's the last frame
                        sampleRec.durationPerSample = ncstream->lastSample.durationPerSample;
                        ncstream->lastSample = sampleRec;
                        ncstream->lastpts = packet.pts;
                } else {
                        ncstream->lastSample.numberOfSamples = 0;
                        
                        if(codecContext->codec_type == CODEC_TYPE_AUDIO && !ncstream->vbr)
                                sampleRec.durationPerSample = 1;
                        else
                                sampleRec.durationPerSample = ncstream->base.num * packet.duration;

                        AddMediaSampleReferences64(ncstream->media, ncstream->sampleHdl, 1, &sampleRec, NULL);
                }
                
                framesProcessed++;
                
                //if we're idling, try really not to read past the end of available data
                //otherwise we will cause blocking i/o.
                if(idling && framesProcessed >= minFrames && availableSize > 0 && availableSize < storage->dataSize) {
                        margin = availableSize - (packet.pos + packet.size);
                        if(margin < (storage->largestPacketSize * 8)) { // 8x fudge factor for comfortable margin, could be tweaked.
                                av_free_packet(&packet);
                                break;
                        }
                }
                
                av_free_packet(&packet);
                
                //stop processing if we've hit the max frame limit
                if(maxFrames > 0 && framesProcessed >= maxFrames)
                        break;
        }
                
        if(readResult != 0) {
                //if readResult != 0, we've hit the end of the stream.