Libav 0.7.1
libavformat/output-example.c
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00001 /*
00002  * Libavformat API example: Output a media file in any supported
00003  * libavformat format. The default codecs are used.
00004  *
00005  * Copyright (c) 2003 Fabrice Bellard
00006  *
00007  * Permission is hereby granted, free of charge, to any person obtaining a copy
00008  * of this software and associated documentation files (the "Software"), to deal
00009  * in the Software without restriction, including without limitation the rights
00010  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00011  * copies of the Software, and to permit persons to whom the Software is
00012  * furnished to do so, subject to the following conditions:
00013  *
00014  * The above copyright notice and this permission notice shall be included in
00015  * all copies or substantial portions of the Software.
00016  *
00017  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00018  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00019  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
00020  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00021  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00022  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00023  * THE SOFTWARE.
00024  */
00025 #include <stdlib.h>
00026 #include <stdio.h>
00027 #include <string.h>
00028 #include <math.h>
00029 
00030 #include "libavformat/avformat.h"
00031 #include "libswscale/swscale.h"
00032 
00033 #undef exit
00034 
00035 /* 5 seconds stream duration */
00036 #define STREAM_DURATION   5.0
00037 #define STREAM_FRAME_RATE 25 /* 25 images/s */
00038 #define STREAM_NB_FRAMES  ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
00039 #define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
00040 
00041 static int sws_flags = SWS_BICUBIC;
00042 
00043 /**************************************************************/
00044 /* audio output */
00045 
00046 float t, tincr, tincr2;
00047 int16_t *samples;
00048 uint8_t *audio_outbuf;
00049 int audio_outbuf_size;
00050 int audio_input_frame_size;
00051 
00052 /*
00053  * add an audio output stream
00054  */
00055 static AVStream *add_audio_stream(AVFormatContext *oc, enum CodecID codec_id)
00056 {
00057     AVCodecContext *c;
00058     AVStream *st;
00059 
00060     st = av_new_stream(oc, 1);
00061     if (!st) {
00062         fprintf(stderr, "Could not alloc stream\n");
00063         exit(1);
00064     }
00065 
00066     c = st->codec;
00067     c->codec_id = codec_id;
00068     c->codec_type = AVMEDIA_TYPE_AUDIO;
00069 
00070     /* put sample parameters */
00071     c->sample_fmt = AV_SAMPLE_FMT_S16;
00072     c->bit_rate = 64000;
00073     c->sample_rate = 44100;
00074     c->channels = 2;
00075 
00076     // some formats want stream headers to be separate
00077     if(oc->oformat->flags & AVFMT_GLOBALHEADER)
00078         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
00079 
00080     return st;
00081 }
00082 
00083 static void open_audio(AVFormatContext *oc, AVStream *st)
00084 {
00085     AVCodecContext *c;
00086     AVCodec *codec;
00087 
00088     c = st->codec;
00089 
00090     /* find the audio encoder */
00091     codec = avcodec_find_encoder(c->codec_id);
00092     if (!codec) {
00093         fprintf(stderr, "codec not found\n");
00094         exit(1);
00095     }
00096 
00097     /* open it */
00098     if (avcodec_open(c, codec) < 0) {
00099         fprintf(stderr, "could not open codec\n");
00100         exit(1);
00101     }
00102 
00103     /* init signal generator */
00104     t = 0;
00105     tincr = 2 * M_PI * 110.0 / c->sample_rate;
00106     /* increment frequency by 110 Hz per second */
00107     tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
00108 
00109     audio_outbuf_size = 10000;
00110     audio_outbuf = av_malloc(audio_outbuf_size);
00111 
00112     /* ugly hack for PCM codecs (will be removed ASAP with new PCM
00113        support to compute the input frame size in samples */
00114     if (c->frame_size <= 1) {
00115         audio_input_frame_size = audio_outbuf_size / c->channels;
00116         switch(st->codec->codec_id) {
00117         case CODEC_ID_PCM_S16LE:
00118         case CODEC_ID_PCM_S16BE:
00119         case CODEC_ID_PCM_U16LE:
00120         case CODEC_ID_PCM_U16BE:
00121             audio_input_frame_size >>= 1;
00122             break;
00123         default:
00124             break;
00125         }
00126     } else {
00127         audio_input_frame_size = c->frame_size;
00128     }
00129     samples = av_malloc(audio_input_frame_size * 2 * c->channels);
00130 }
00131 
00132 /* prepare a 16 bit dummy audio frame of 'frame_size' samples and
00133    'nb_channels' channels */
00134 static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
00135 {
00136     int j, i, v;
00137     int16_t *q;
00138 
00139     q = samples;
00140     for(j=0;j<frame_size;j++) {
00141         v = (int)(sin(t) * 10000);
00142         for(i = 0; i < nb_channels; i++)
00143             *q++ = v;
00144         t += tincr;
00145         tincr += tincr2;
00146     }
00147 }
00148 
00149 static void write_audio_frame(AVFormatContext *oc, AVStream *st)
00150 {
00151     AVCodecContext *c;
00152     AVPacket pkt;
00153     av_init_packet(&pkt);
00154 
00155     c = st->codec;
00156 
00157     get_audio_frame(samples, audio_input_frame_size, c->channels);
00158 
00159     pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
00160 
00161     if (c->coded_frame && c->coded_frame->pts != AV_NOPTS_VALUE)
00162         pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
00163     pkt.flags |= AV_PKT_FLAG_KEY;
00164     pkt.stream_index= st->index;
00165     pkt.data= audio_outbuf;
00166 
00167     /* write the compressed frame in the media file */
00168     if (av_interleaved_write_frame(oc, &pkt) != 0) {
00169         fprintf(stderr, "Error while writing audio frame\n");
00170         exit(1);
00171     }
00172 }
00173 
00174 static void close_audio(AVFormatContext *oc, AVStream *st)
00175 {
00176     avcodec_close(st->codec);
00177 
00178     av_free(samples);
00179     av_free(audio_outbuf);
00180 }
00181 
00182 /**************************************************************/
00183 /* video output */
00184 
00185 AVFrame *picture, *tmp_picture;
00186 uint8_t *video_outbuf;
00187 int frame_count, video_outbuf_size;
00188 
00189 /* add a video output stream */
00190 static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id)
00191 {
00192     AVCodecContext *c;
00193     AVStream *st;
00194 
00195     st = av_new_stream(oc, 0);
00196     if (!st) {
00197         fprintf(stderr, "Could not alloc stream\n");
00198         exit(1);
00199     }
00200 
00201     c = st->codec;
00202     c->codec_id = codec_id;
00203     c->codec_type = AVMEDIA_TYPE_VIDEO;
00204 
00205     /* put sample parameters */
00206     c->bit_rate = 400000;
00207     /* resolution must be a multiple of two */
00208     c->width = 352;
00209     c->height = 288;
00210     /* time base: this is the fundamental unit of time (in seconds) in terms
00211        of which frame timestamps are represented. for fixed-fps content,
00212        timebase should be 1/framerate and timestamp increments should be
00213        identically 1. */
00214     c->time_base.den = STREAM_FRAME_RATE;
00215     c->time_base.num = 1;
00216     c->gop_size = 12; /* emit one intra frame every twelve frames at most */
00217     c->pix_fmt = STREAM_PIX_FMT;
00218     if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
00219         /* just for testing, we also add B frames */
00220         c->max_b_frames = 2;
00221     }
00222     if (c->codec_id == CODEC_ID_MPEG1VIDEO){
00223         /* Needed to avoid using macroblocks in which some coeffs overflow.
00224            This does not happen with normal video, it just happens here as
00225            the motion of the chroma plane does not match the luma plane. */
00226         c->mb_decision=2;
00227     }
00228     // some formats want stream headers to be separate
00229     if(oc->oformat->flags & AVFMT_GLOBALHEADER)
00230         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
00231 
00232     return st;
00233 }
00234 
00235 static AVFrame *alloc_picture(enum PixelFormat pix_fmt, int width, int height)
00236 {
00237     AVFrame *picture;
00238     uint8_t *picture_buf;
00239     int size;
00240 
00241     picture = avcodec_alloc_frame();
00242     if (!picture)
00243         return NULL;
00244     size = avpicture_get_size(pix_fmt, width, height);
00245     picture_buf = av_malloc(size);
00246     if (!picture_buf) {
00247         av_free(picture);
00248         return NULL;
00249     }
00250     avpicture_fill((AVPicture *)picture, picture_buf,
00251                    pix_fmt, width, height);
00252     return picture;
00253 }
00254 
00255 static void open_video(AVFormatContext *oc, AVStream *st)
00256 {
00257     AVCodec *codec;
00258     AVCodecContext *c;
00259 
00260     c = st->codec;
00261 
00262     /* find the video encoder */
00263     codec = avcodec_find_encoder(c->codec_id);
00264     if (!codec) {
00265         fprintf(stderr, "codec not found\n");
00266         exit(1);
00267     }
00268 
00269     /* open the codec */
00270     if (avcodec_open(c, codec) < 0) {
00271         fprintf(stderr, "could not open codec\n");
00272         exit(1);
00273     }
00274 
00275     video_outbuf = NULL;
00276     if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
00277         /* allocate output buffer */
00278         /* XXX: API change will be done */
00279         /* buffers passed into lav* can be allocated any way you prefer,
00280            as long as they're aligned enough for the architecture, and
00281            they're freed appropriately (such as using av_free for buffers
00282            allocated with av_malloc) */
00283         video_outbuf_size = 200000;
00284         video_outbuf = av_malloc(video_outbuf_size);
00285     }
00286 
00287     /* allocate the encoded raw picture */
00288     picture = alloc_picture(c->pix_fmt, c->width, c->height);
00289     if (!picture) {
00290         fprintf(stderr, "Could not allocate picture\n");
00291         exit(1);
00292     }
00293 
00294     /* if the output format is not YUV420P, then a temporary YUV420P
00295        picture is needed too. It is then converted to the required
00296        output format */
00297     tmp_picture = NULL;
00298     if (c->pix_fmt != PIX_FMT_YUV420P) {
00299         tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
00300         if (!tmp_picture) {
00301             fprintf(stderr, "Could not allocate temporary picture\n");
00302             exit(1);
00303         }
00304     }
00305 }
00306 
00307 /* prepare a dummy image */
00308 static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
00309 {
00310     int x, y, i;
00311 
00312     i = frame_index;
00313 
00314     /* Y */
00315     for(y=0;y<height;y++) {
00316         for(x=0;x<width;x++) {
00317             pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
00318         }
00319     }
00320 
00321     /* Cb and Cr */
00322     for(y=0;y<height/2;y++) {
00323         for(x=0;x<width/2;x++) {
00324             pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
00325             pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
00326         }
00327     }
00328 }
00329 
00330 static void write_video_frame(AVFormatContext *oc, AVStream *st)
00331 {
00332     int out_size, ret;
00333     AVCodecContext *c;
00334     static struct SwsContext *img_convert_ctx;
00335 
00336     c = st->codec;
00337 
00338     if (frame_count >= STREAM_NB_FRAMES) {
00339         /* no more frame to compress. The codec has a latency of a few
00340            frames if using B frames, so we get the last frames by
00341            passing the same picture again */
00342     } else {
00343         if (c->pix_fmt != PIX_FMT_YUV420P) {
00344             /* as we only generate a YUV420P picture, we must convert it
00345                to the codec pixel format if needed */
00346             if (img_convert_ctx == NULL) {
00347                 img_convert_ctx = sws_getContext(c->width, c->height,
00348                                                  PIX_FMT_YUV420P,
00349                                                  c->width, c->height,
00350                                                  c->pix_fmt,
00351                                                  sws_flags, NULL, NULL, NULL);
00352                 if (img_convert_ctx == NULL) {
00353                     fprintf(stderr, "Cannot initialize the conversion context\n");
00354                     exit(1);
00355                 }
00356             }
00357             fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
00358             sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
00359                       0, c->height, picture->data, picture->linesize);
00360         } else {
00361             fill_yuv_image(picture, frame_count, c->width, c->height);
00362         }
00363     }
00364 
00365 
00366     if (oc->oformat->flags & AVFMT_RAWPICTURE) {
00367         /* raw video case. The API will change slightly in the near
00368            futur for that */
00369         AVPacket pkt;
00370         av_init_packet(&pkt);
00371 
00372         pkt.flags |= AV_PKT_FLAG_KEY;
00373         pkt.stream_index= st->index;
00374         pkt.data= (uint8_t *)picture;
00375         pkt.size= sizeof(AVPicture);
00376 
00377         ret = av_interleaved_write_frame(oc, &pkt);
00378     } else {
00379         /* encode the image */
00380         out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
00381         /* if zero size, it means the image was buffered */
00382         if (out_size > 0) {
00383             AVPacket pkt;
00384             av_init_packet(&pkt);
00385 
00386             if (c->coded_frame->pts != AV_NOPTS_VALUE)
00387                 pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
00388             if(c->coded_frame->key_frame)
00389                 pkt.flags |= AV_PKT_FLAG_KEY;
00390             pkt.stream_index= st->index;
00391             pkt.data= video_outbuf;
00392             pkt.size= out_size;
00393 
00394             /* write the compressed frame in the media file */
00395             ret = av_interleaved_write_frame(oc, &pkt);
00396         } else {
00397             ret = 0;
00398         }
00399     }
00400     if (ret != 0) {
00401         fprintf(stderr, "Error while writing video frame\n");
00402         exit(1);
00403     }
00404     frame_count++;
00405 }
00406 
00407 static void close_video(AVFormatContext *oc, AVStream *st)
00408 {
00409     avcodec_close(st->codec);
00410     av_free(picture->data[0]);
00411     av_free(picture);
00412     if (tmp_picture) {
00413         av_free(tmp_picture->data[0]);
00414         av_free(tmp_picture);
00415     }
00416     av_free(video_outbuf);
00417 }
00418 
00419 /**************************************************************/
00420 /* media file output */
00421 
00422 int main(int argc, char **argv)
00423 {
00424     const char *filename;
00425     AVOutputFormat *fmt;
00426     AVFormatContext *oc;
00427     AVStream *audio_st, *video_st;
00428     double audio_pts, video_pts;
00429     int i;
00430 
00431     /* initialize libavcodec, and register all codecs and formats */
00432     av_register_all();
00433 
00434     if (argc != 2) {
00435         printf("usage: %s output_file\n"
00436                "API example program to output a media file with libavformat.\n"
00437                "The output format is automatically guessed according to the file extension.\n"
00438                "Raw images can also be output by using '%%d' in the filename\n"
00439                "\n", argv[0]);
00440         exit(1);
00441     }
00442 
00443     filename = argv[1];
00444 
00445     /* auto detect the output format from the name. default is
00446        mpeg. */
00447     fmt = av_guess_format(NULL, filename, NULL);
00448     if (!fmt) {
00449         printf("Could not deduce output format from file extension: using MPEG.\n");
00450         fmt = av_guess_format("mpeg", NULL, NULL);
00451     }
00452     if (!fmt) {
00453         fprintf(stderr, "Could not find suitable output format\n");
00454         exit(1);
00455     }
00456 
00457     /* allocate the output media context */
00458     oc = avformat_alloc_context();
00459     if (!oc) {
00460         fprintf(stderr, "Memory error\n");
00461         exit(1);
00462     }
00463     oc->oformat = fmt;
00464     snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
00465 
00466     /* add the audio and video streams using the default format codecs
00467        and initialize the codecs */
00468     video_st = NULL;
00469     audio_st = NULL;
00470     if (fmt->video_codec != CODEC_ID_NONE) {
00471         video_st = add_video_stream(oc, fmt->video_codec);
00472     }
00473     if (fmt->audio_codec != CODEC_ID_NONE) {
00474         audio_st = add_audio_stream(oc, fmt->audio_codec);
00475     }
00476 
00477     /* set the output parameters (must be done even if no
00478        parameters). */
00479     if (av_set_parameters(oc, NULL) < 0) {
00480         fprintf(stderr, "Invalid output format parameters\n");
00481         exit(1);
00482     }
00483 
00484     av_dump_format(oc, 0, filename, 1);
00485 
00486     /* now that all the parameters are set, we can open the audio and
00487        video codecs and allocate the necessary encode buffers */
00488     if (video_st)
00489         open_video(oc, video_st);
00490     if (audio_st)
00491         open_audio(oc, audio_st);
00492 
00493     /* open the output file, if needed */
00494     if (!(fmt->flags & AVFMT_NOFILE)) {
00495         if (avio_open(&oc->pb, filename, AVIO_FLAG_WRITE) < 0) {
00496             fprintf(stderr, "Could not open '%s'\n", filename);
00497             exit(1);
00498         }
00499     }
00500 
00501     /* write the stream header, if any */
00502     av_write_header(oc);
00503 
00504     for(;;) {
00505         /* compute current audio and video time */
00506         if (audio_st)
00507             audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
00508         else
00509             audio_pts = 0.0;
00510 
00511         if (video_st)
00512             video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
00513         else
00514             video_pts = 0.0;
00515 
00516         if ((!audio_st || audio_pts >= STREAM_DURATION) &&
00517             (!video_st || video_pts >= STREAM_DURATION))
00518             break;
00519 
00520         /* write interleaved audio and video frames */
00521         if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
00522             write_audio_frame(oc, audio_st);
00523         } else {
00524             write_video_frame(oc, video_st);
00525         }
00526     }
00527 
00528     /* write the trailer, if any.  the trailer must be written
00529      * before you close the CodecContexts open when you wrote the
00530      * header; otherwise write_trailer may try to use memory that
00531      * was freed on av_codec_close() */
00532     av_write_trailer(oc);
00533 
00534     /* close each codec */
00535     if (video_st)
00536         close_video(oc, video_st);
00537     if (audio_st)
00538         close_audio(oc, audio_st);
00539 
00540     /* free the streams */
00541     for(i = 0; i < oc->nb_streams; i++) {
00542         av_freep(&oc->streams[i]->codec);
00543         av_freep(&oc->streams[i]);
00544     }
00545 
00546     if (!(fmt->flags & AVFMT_NOFILE)) {
00547         /* close the output file */
00548         avio_close(oc->pb);
00549     }
00550 
00551     /* free the stream */
00552     av_free(oc);
00553 
00554     return 0;
00555 }