@@ -36,7 +36,7 @@

 /doc/avoptions_format.texi

 /doc/doxy/html/

 /doc/examples/avio_reading

-/doc/examples/avcodec

+/doc/examples/decoding_encoding

 /doc/examples/demuxing_decoding

 /doc/examples/filter_audio

 /doc/examples/filtering_audio

@@ -1284,7 +1284,7 @@ COMPONENT_LIST="

 EXAMPLE_LIST="

     avio_reading_example

-    avcodec_example

+    decoding_encoding_example

     demuxing_decoding_example

     filter_audio_example

     filtering_audio_example

@@ -12,7 +12,7 @@ CFLAGS := $(shell pkg-config --cflags $(FFMPEG_LIBS)) $(CFLAGS)

 LDLIBS := $(shell pkg-config --libs $(FFMPEG_LIBS)) $(LDLIBS)

 EXAMPLES=       avio_reading                       \

-                avcodec                            \

+                decoding_encoding                  \

                 demuxing_decoding                  \

                 filtering_video                    \

                 filtering_audio                    \

deleted file mode 100644

@@ -1,664 +0,0 @@

-/*

- * Copyright (c) 2001 Fabrice Bellard

- *

- * Permission is hereby granted, free of charge, to any person obtaining a copy

- * of this software and associated documentation files (the "Software"), to deal

- * in the Software without restriction, including without limitation the rights

- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

- * copies of the Software, and to permit persons to whom the Software is

- * furnished to do so, subject to the following conditions:

- *

- * The above copyright notice and this permission notice shall be included in

- * all copies or substantial portions of the Software.

- *

- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

- * THE SOFTWARE.

- */

-

-/**

- * @file

- * libavcodec API use example.

- *

- * @example avcodec.c

- * Note that libavcodec only handles codecs (mpeg, mpeg4, etc...),

- * not file formats (avi, vob, mp4, mov, mkv, mxf, flv, mpegts, mpegps, etc...). See library 'libavformat' for the

- * format handling

- */

-

-#include <math.h>

-

-#include <libavutil/opt.h>

-#include <libavcodec/avcodec.h>

-#include <libavutil/channel_layout.h>

-#include <libavutil/common.h>

-#include <libavutil/imgutils.h>

-#include <libavutil/mathematics.h>

-#include <libavutil/samplefmt.h>

-

-#define INBUF_SIZE 4096

-#define AUDIO_INBUF_SIZE 20480

-#define AUDIO_REFILL_THRESH 4096

-

-/* check that a given sample format is supported by the encoder */

-static int check_sample_fmt(AVCodec *codec, enum AVSampleFormat sample_fmt)

-{

-    const enum AVSampleFormat *p = codec->sample_fmts;

-

-    while (*p != AV_SAMPLE_FMT_NONE) {

-        if (*p == sample_fmt)

-            return 1;

-        p++;

-    }

-    return 0;

-}

-

-/* just pick the highest supported samplerate */

-static int select_sample_rate(AVCodec *codec)

-{

-    const int *p;

-    int best_samplerate = 0;

-

-    if (!codec->supported_samplerates)

-        return 44100;

-

-    p = codec->supported_samplerates;

-    while (*p) {

-        best_samplerate = FFMAX(*p, best_samplerate);

-        p++;

-    }

-    return best_samplerate;

-}

-

-/* select layout with the highest channel count */

-static int select_channel_layout(AVCodec *codec)

-{

-    const uint64_t *p;

-    uint64_t best_ch_layout = 0;

-    int best_nb_channels   = 0;

-

-    if (!codec->channel_layouts)

-        return AV_CH_LAYOUT_STEREO;

-

-    p = codec->channel_layouts;

-    while (*p) {

-        int nb_channels = av_get_channel_layout_nb_channels(*p);

-

-        if (nb_channels > best_nb_channels) {

-            best_ch_layout    = *p;

-            best_nb_channels = nb_channels;

-        }

-        p++;

-    }

-    return best_ch_layout;

-}

-

-/*

- * Audio encoding example

- */

-static void audio_encode_example(const char *filename)

-{

-    AVCodec *codec;

-    AVCodecContext *c= NULL;

-    AVFrame *frame;

-    AVPacket pkt;

-    int i, j, k, ret, got_output;

-    int buffer_size;

-    FILE *f;

-    uint16_t *samples;

-    float t, tincr;

-

-    printf("Encode audio file %s\n", filename);

-

-    /* find the MP2 encoder */

-    codec = avcodec_find_encoder(AV_CODEC_ID_MP2);

-    if (!codec) {

-        fprintf(stderr, "Codec not found\n");

-        exit(1);

-    }

-

-    c = avcodec_alloc_context3(codec);

-    if (!c) {

-        fprintf(stderr, "Could not allocate audio codec context\n");

-        exit(1);

-    }

-

-    /* put sample parameters */

-    c->bit_rate = 64000;

-

-    /* check that the encoder supports s16 pcm input */

-    c->sample_fmt = AV_SAMPLE_FMT_S16;

-    if (!check_sample_fmt(codec, c->sample_fmt)) {

-        fprintf(stderr, "Encoder does not support sample format %s",

-                av_get_sample_fmt_name(c->sample_fmt));

-        exit(1);

-    }

-

-    /* select other audio parameters supported by the encoder */

-    c->sample_rate    = select_sample_rate(codec);

-    c->channel_layout = select_channel_layout(codec);

-    c->channels       = av_get_channel_layout_nb_channels(c->channel_layout);

-

-    /* open it */

-    if (avcodec_open2(c, codec, NULL) < 0) {

-        fprintf(stderr, "Could not open codec\n");

-        exit(1);

-    }

-

-    f = fopen(filename, "wb");

-    if (!f) {

-        fprintf(stderr, "Could not open %s\n", filename);

-        exit(1);

-    }

-

-    /* frame containing input raw audio */

-    frame = av_frame_alloc();

-    if (!frame) {

-        fprintf(stderr, "Could not allocate audio frame\n");

-        exit(1);

-    }

-

-    frame->nb_samples     = c->frame_size;

-    frame->format         = c->sample_fmt;

-    frame->channel_layout = c->channel_layout;

-

-    /* the codec gives us the frame size, in samples,

-     * we calculate the size of the samples buffer in bytes */

-    buffer_size = av_samples_get_buffer_size(NULL, c->channels, c->frame_size,

-                                             c->sample_fmt, 0);

-    if (buffer_size < 0) {

-        fprintf(stderr, "Could not get sample buffer size\n");

-        exit(1);

-    }

-    samples = av_malloc(buffer_size);

-    if (!samples) {

-        fprintf(stderr, "Could not allocate %d bytes for samples buffer\n",

-                buffer_size);

-        exit(1);

-    }

-    /* setup the data pointers in the AVFrame */

-    ret = avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt,

-                                   (const uint8_t*)samples, buffer_size, 0);

-    if (ret < 0) {

-        fprintf(stderr, "Could not setup audio frame\n");

-        exit(1);

-    }

-

-    /* encode a single tone sound */

-    t = 0;

-    tincr = 2 * M_PI * 440.0 / c->sample_rate;

-    for (i = 0; i < 200; i++) {

-        av_init_packet(&pkt);

-        pkt.data = NULL; // packet data will be allocated by the encoder

-        pkt.size = 0;

-

-        for (j = 0; j < c->frame_size; j++) {

-            samples[2*j] = (int)(sin(t) * 10000);

-

-            for (k = 1; k < c->channels; k++)

-                samples[2*j + k] = samples[2*j];

-            t += tincr;

-        }

-        /* encode the samples */

-        ret = avcodec_encode_audio2(c, &pkt, frame, &got_output);

-        if (ret < 0) {

-            fprintf(stderr, "Error encoding audio frame\n");

-            exit(1);

-        }

-        if (got_output) {

-            fwrite(pkt.data, 1, pkt.size, f);

-            av_free_packet(&pkt);

-        }

-    }

-

-    /* get the delayed frames */

-    for (got_output = 1; got_output; i++) {

-        ret = avcodec_encode_audio2(c, &pkt, NULL, &got_output);

-        if (ret < 0) {

-            fprintf(stderr, "Error encoding frame\n");

-            exit(1);

-        }

-

-        if (got_output) {

-            fwrite(pkt.data, 1, pkt.size, f);

-            av_free_packet(&pkt);

-        }

-    }

-    fclose(f);

-

-    av_freep(&samples);

-    av_frame_free(&frame);

-    avcodec_close(c);

-    av_free(c);

-}

-

-/*

- * Audio decoding.

- */

-static void audio_decode_example(const char *outfilename, const char *filename)

-{

-    AVCodec *codec;

-    AVCodecContext *c= NULL;

-    int len;

-    FILE *f, *outfile;

-    uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];

-    AVPacket avpkt;

-    AVFrame *decoded_frame = NULL;

-

-    av_init_packet(&avpkt);

-

-    printf("Decode audio file %s to %s\n", filename, outfilename);

-

-    /* find the mpeg audio decoder */

-    codec = avcodec_find_decoder(AV_CODEC_ID_MP2);

-    if (!codec) {

-        fprintf(stderr, "Codec not found\n");

-        exit(1);

-    }

-

-    c = avcodec_alloc_context3(codec);

-    if (!c) {

-        fprintf(stderr, "Could not allocate audio codec context\n");

-        exit(1);

-    }

-

-    /* open it */

-    if (avcodec_open2(c, codec, NULL) < 0) {

-        fprintf(stderr, "Could not open codec\n");

-        exit(1);

-    }

-

-    f = fopen(filename, "rb");

-    if (!f) {

-        fprintf(stderr, "Could not open %s\n", filename);

-        exit(1);

-    }

-    outfile = fopen(outfilename, "wb");

-    if (!outfile) {

-        av_free(c);

-        exit(1);

-    }

-

-    /* decode until eof */

-    avpkt.data = inbuf;

-    avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f);

-

-    while (avpkt.size > 0) {

-        int got_frame = 0;

-

-        if (!decoded_frame) {

-            if (!(decoded_frame = av_frame_alloc())) {

-                fprintf(stderr, "Could not allocate audio frame\n");

-                exit(1);

-            }

-        }

-

-        len = avcodec_decode_audio4(c, decoded_frame, &got_frame, &avpkt);

-        if (len < 0) {

-            fprintf(stderr, "Error while decoding\n");

-            exit(1);

-        }

-        if (got_frame) {

-            /* if a frame has been decoded, output it */

-            int data_size = av_samples_get_buffer_size(NULL, c->channels,

-                                                       decoded_frame->nb_samples,

-                                                       c->sample_fmt, 1);

-            if (data_size < 0) {

-                /* This should not occur, checking just for paranoia */

-                fprintf(stderr, "Failed to calculate data size\n");

-                exit(1);

-            }

-            fwrite(decoded_frame->data[0], 1, data_size, outfile);

-        }

-        avpkt.size -= len;

-        avpkt.data += len;

-        avpkt.dts =

-        avpkt.pts = AV_NOPTS_VALUE;

-        if (avpkt.size < AUDIO_REFILL_THRESH) {

-            /* Refill the input buffer, to avoid trying to decode

-             * incomplete frames. Instead of this, one could also use

-             * a parser, or use a proper container format through

-             * libavformat. */

-            memmove(inbuf, avpkt.data, avpkt.size);

-            avpkt.data = inbuf;

-            len = fread(avpkt.data + avpkt.size, 1,

-                        AUDIO_INBUF_SIZE - avpkt.size, f);

-            if (len > 0)

-                avpkt.size += len;

-        }

-    }

-

-    fclose(outfile);

-    fclose(f);

-

-    avcodec_close(c);

-    av_free(c);

-    av_frame_free(&decoded_frame);

-}

-

-/*

- * Video encoding example

- */

-static void video_encode_example(const char *filename, int codec_id)

-{

-    AVCodec *codec;

-    AVCodecContext *c= NULL;

-    int i, ret, x, y, got_output;

-    FILE *f;

-    AVFrame *frame;

-    AVPacket pkt;

-    uint8_t endcode[] = { 0, 0, 1, 0xb7 };

-

-    printf("Encode video file %s\n", filename);

-

-    /* find the mpeg1 video encoder */

-    codec = avcodec_find_encoder(codec_id);

-    if (!codec) {

-        fprintf(stderr, "Codec not found\n");

-        exit(1);

-    }

-

-    c = avcodec_alloc_context3(codec);

-    if (!c) {

-        fprintf(stderr, "Could not allocate video codec context\n");

-        exit(1);

-    }

-

-    /* put sample parameters */

-    c->bit_rate = 400000;

-    /* resolution must be a multiple of two */

-    c->width = 352;

-    c->height = 288;

-    /* frames per second */

-    c->time_base = (AVRational){1,25};

-    /* emit one intra frame every ten frames

-     * check frame pict_type before passing frame

-     * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I

-     * then gop_size is ignored and the output of encoder

-     * will always be I frame irrespective to gop_size

-     */

-    c->gop_size = 10;

-    c->max_b_frames = 1;

-    c->pix_fmt = AV_PIX_FMT_YUV420P;

-

-    if (codec_id == AV_CODEC_ID_H264)

-        av_opt_set(c->priv_data, "preset", "slow", 0);

-

-    /* open it */

-    if (avcodec_open2(c, codec, NULL) < 0) {

-        fprintf(stderr, "Could not open codec\n");

-        exit(1);

-    }

-

-    f = fopen(filename, "wb");

-    if (!f) {

-        fprintf(stderr, "Could not open %s\n", filename);

-        exit(1);

-    }

-

-    frame = av_frame_alloc();

-    if (!frame) {

-        fprintf(stderr, "Could not allocate video frame\n");

-        exit(1);

-    }

-    frame->format = c->pix_fmt;

-    frame->width  = c->width;

-    frame->height = c->height;

-

-    /* the image can be allocated by any means and av_image_alloc() is

-     * just the most convenient way if av_malloc() is to be used */

-    ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height,

-                         c->pix_fmt, 32);

-    if (ret < 0) {

-        fprintf(stderr, "Could not allocate raw picture buffer\n");

-        exit(1);

-    }

-

-    /* encode 1 second of video */

-    for (i = 0; i < 25; i++) {

-        av_init_packet(&pkt);

-        pkt.data = NULL;    // packet data will be allocated by the encoder

-        pkt.size = 0;

-

-        fflush(stdout);

-        /* prepare a dummy image */

-        /* Y */

-        for (y = 0; y < c->height; y++) {

-            for (x = 0; x < c->width; x++) {

-                frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;

-            }

-        }

-

-        /* Cb and Cr */

-        for (y = 0; y < c->height/2; y++) {

-            for (x = 0; x < c->width/2; x++) {

-                frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;

-                frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;

-            }

-        }

-

-        frame->pts = i;

-

-        /* encode the image */

-        ret = avcodec_encode_video2(c, &pkt, frame, &got_output);

-        if (ret < 0) {

-            fprintf(stderr, "Error encoding frame\n");

-            exit(1);

-        }

-

-        if (got_output) {

-            printf("Write frame %3d (size=%5d)\n", i, pkt.size);

-            fwrite(pkt.data, 1, pkt.size, f);

-            av_free_packet(&pkt);

-        }

-    }

-

-    /* get the delayed frames */

-    for (got_output = 1; got_output; i++) {

-        fflush(stdout);

-

-        ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);

-        if (ret < 0) {

-            fprintf(stderr, "Error encoding frame\n");

-            exit(1);

-        }

-

-        if (got_output) {

-            printf("Write frame %3d (size=%5d)\n", i, pkt.size);

-            fwrite(pkt.data, 1, pkt.size, f);

-            av_free_packet(&pkt);

-        }

-    }

-

-    /* add sequence end code to have a real mpeg file */

-    fwrite(endcode, 1, sizeof(endcode), f);

-    fclose(f);

-

-    avcodec_close(c);

-    av_free(c);

-    av_freep(&frame->data[0]);

-    av_frame_free(&frame);

-    printf("\n");

-}

-

-/*

- * Video decoding example

- */

-

-static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,

-                     char *filename)

-{

-    FILE *f;

-    int i;

-

-    f = fopen(filename,"w");

-    fprintf(f, "P5\n%d %d\n%d\n", xsize, ysize, 255);

-    for (i = 0; i < ysize; i++)

-        fwrite(buf + i * wrap, 1, xsize, f);

-    fclose(f);

-}

-

-static int decode_write_frame(const char *outfilename, AVCodecContext *avctx,

-                              AVFrame *frame, int *frame_count, AVPacket *pkt, int last)

-{

-    int len, got_frame;

-    char buf[1024];

-

-    len = avcodec_decode_video2(avctx, frame, &got_frame, pkt);

-    if (len < 0) {

-        fprintf(stderr, "Error while decoding frame %d\n", *frame_count);

-        return len;

-    }

-    if (got_frame) {

-        printf("Saving %sframe %3d\n", last ? "last " : "", *frame_count);

-        fflush(stdout);

-

-        /* the picture is allocated by the decoder, no need to free it */

-        snprintf(buf, sizeof(buf), outfilename, *frame_count);

-        pgm_save(frame->data[0], frame->linesize[0],

-                 avctx->width, avctx->height, buf);

-        (*frame_count)++;

-    }

-    if (pkt->data) {

-        pkt->size -= len;

-        pkt->data += len;

-    }

-    return 0;

-}

-

-static void video_decode_example(const char *outfilename, const char *filename)

-{

-    AVCodec *codec;

-    AVCodecContext *c= NULL;

-    int frame_count;

-    FILE *f;

-    AVFrame *frame;

-    uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];

-    AVPacket avpkt;

-

-    av_init_packet(&avpkt);

-

-    /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */

-    memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);

-

-    printf("Decode video file %s to %s\n", filename, outfilename);

-

-    /* find the mpeg1 video decoder */

-    codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);

-    if (!codec) {

-        fprintf(stderr, "Codec not found\n");

-        exit(1);

-    }

-

-    c = avcodec_alloc_context3(codec);

-    if (!c) {

-        fprintf(stderr, "Could not allocate video codec context\n");

-        exit(1);

-    }

-

-    if(codec->capabilities&CODEC_CAP_TRUNCATED)

-        c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete frames */

-

-    /* For some codecs, such as msmpeg4 and mpeg4, width and height

-       MUST be initialized there because this information is not

-       available in the bitstream. */

-

-    /* open it */

-    if (avcodec_open2(c, codec, NULL) < 0) {

-        fprintf(stderr, "Could not open codec\n");

-        exit(1);

-    }

-

-    f = fopen(filename, "rb");

-    if (!f) {

-        fprintf(stderr, "Could not open %s\n", filename);

-        exit(1);

-    }

-

-    frame = av_frame_alloc();

-    if (!frame) {

-        fprintf(stderr, "Could not allocate video frame\n");

-        exit(1);

-    }

-

-    frame_count = 0;

-    for (;;) {

-        avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);

-        if (avpkt.size == 0)

-            break;

-

-        /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)

-           and this is the only method to use them because you cannot

-           know the compressed data size before analysing it.

-

-           BUT some other codecs (msmpeg4, mpeg4) are inherently frame

-           based, so you must call them with all the data for one

-           frame exactly. You must also initialize 'width' and

-           'height' before initializing them. */

-

-        /* NOTE2: some codecs allow the raw parameters (frame size,

-           sample rate) to be changed at any frame. We handle this, so

-           you should also take care of it */

-

-        /* here, we use a stream based decoder (mpeg1video), so we

-           feed decoder and see if it could decode a frame */

-        avpkt.data = inbuf;

-        while (avpkt.size > 0)

-            if (decode_write_frame(outfilename, c, frame, &frame_count, &avpkt, 0) < 0)

-                exit(1);

-    }

-

-    /* some codecs, such as MPEG, transmit the I and P frame with a

-       latency of one frame. You must do the following to have a

-       chance to get the last frame of the video */

-    avpkt.data = NULL;

-    avpkt.size = 0;

-    decode_write_frame(outfilename, c, frame, &frame_count, &avpkt, 1);

-

-    fclose(f);

-

-    avcodec_close(c);

-    av_free(c);

-    av_frame_free(&frame);

-    printf("\n");

-}

-

-int main(int argc, char **argv)

-{

-    const char *output_type;

-

-    /* register all the codecs */

-    avcodec_register_all();

-

-    if (argc < 2) {

-        printf("usage: %s output_type\n"

-               "API example program to decode/encode a media stream with libavcodec.\n"

-               "This program generates a synthetic stream and encodes it to a file\n"

-               "named test.h264, test.mp2 or test.mpg depending on output_type.\n"

-               "The encoded stream is then decoded and written to a raw data output.\n"

-               "output_type must be choosen between 'h264', 'mp2', 'mpg'.\n",

-               argv[0]);

-        return 1;

-    }

-    output_type = argv[1];

-

-    if (!strcmp(output_type, "h264")) {

-        video_encode_example("test.h264", AV_CODEC_ID_H264);

-    } else if (!strcmp(output_type, "mp2")) {

-        audio_encode_example("test.mp2");

-        audio_decode_example("test.sw", "test.mp2");

-    } else if (!strcmp(output_type, "mpg")) {

-        video_encode_example("test.mpg", AV_CODEC_ID_MPEG1VIDEO);

-        video_decode_example("test%02d.pgm", "test.mpg");

-    } else {

-        fprintf(stderr, "Invalid output type '%s', choose between 'h264', 'mp2', or 'mpg'\n",

-                output_type);

-        return 1;

-    }

-

-    return 0;

-}

new file mode 100644

@@ -0,0 +1,664 @@

+/*

+ * Copyright (c) 2001 Fabrice Bellard

+ *

+ * Permission is hereby granted, free of charge, to any person obtaining a copy

+ * of this software and associated documentation files (the "Software"), to deal

+ * in the Software without restriction, including without limitation the rights

+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

+ * copies of the Software, and to permit persons to whom the Software is

+ * furnished to do so, subject to the following conditions:

+ *

+ * The above copyright notice and this permission notice shall be included in

+ * all copies or substantial portions of the Software.

+ *

+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

+ * THE SOFTWARE.

+ */

+

+/**

+ * @file

+ * libavcodec API use example.

+ *

+ * @example decoding_encoding.c

+ * Note that libavcodec only handles codecs (mpeg, mpeg4, etc...),

+ * not file formats (avi, vob, mp4, mov, mkv, mxf, flv, mpegts, mpegps, etc...). See library 'libavformat' for the

+ * format handling

+ */

+

+#include <math.h>

+

+#include <libavutil/opt.h>

+#include <libavcodec/avcodec.h>

+#include <libavutil/channel_layout.h>

+#include <libavutil/common.h>

+#include <libavutil/imgutils.h>

+#include <libavutil/mathematics.h>

+#include <libavutil/samplefmt.h>

+

+#define INBUF_SIZE 4096

+#define AUDIO_INBUF_SIZE 20480

+#define AUDIO_REFILL_THRESH 4096

+

+/* check that a given sample format is supported by the encoder */

+static int check_sample_fmt(AVCodec *codec, enum AVSampleFormat sample_fmt)

+{

+    const enum AVSampleFormat *p = codec->sample_fmts;

+

+    while (*p != AV_SAMPLE_FMT_NONE) {

+        if (*p == sample_fmt)

+            return 1;

+        p++;

+    }

+    return 0;

+}

+

+/* just pick the highest supported samplerate */

+static int select_sample_rate(AVCodec *codec)

+{

+    const int *p;

+    int best_samplerate = 0;

+

+    if (!codec->supported_samplerates)

+        return 44100;

+

+    p = codec->supported_samplerates;

+    while (*p) {

+        best_samplerate = FFMAX(*p, best_samplerate);

+        p++;

+    }

+    return best_samplerate;

+}

+

+/* select layout with the highest channel count */

+static int select_channel_layout(AVCodec *codec)

+{

+    const uint64_t *p;

+    uint64_t best_ch_layout = 0;

+    int best_nb_channels   = 0;

+

+    if (!codec->channel_layouts)

+        return AV_CH_LAYOUT_STEREO;

+

+    p = codec->channel_layouts;

+    while (*p) {

+        int nb_channels = av_get_channel_layout_nb_channels(*p);

+

+        if (nb_channels > best_nb_channels) {

+            best_ch_layout    = *p;

+            best_nb_channels = nb_channels;

+        }

+        p++;

+    }

+    return best_ch_layout;

+}

+

+/*

+ * Audio encoding example

+ */

+static void audio_encode_example(const char *filename)

+{

+    AVCodec *codec;

+    AVCodecContext *c= NULL;

+    AVFrame *frame;

+    AVPacket pkt;

+    int i, j, k, ret, got_output;

+    int buffer_size;

+    FILE *f;

+    uint16_t *samples;

+    float t, tincr;

+

+    printf("Encode audio file %s\n", filename);

+

+    /* find the MP2 encoder */

+    codec = avcodec_find_encoder(AV_CODEC_ID_MP2);

+    if (!codec) {

+        fprintf(stderr, "Codec not found\n");

+        exit(1);

+    }

+

+    c = avcodec_alloc_context3(codec);

+    if (!c) {

+        fprintf(stderr, "Could not allocate audio codec context\n");

+        exit(1);

+    }

+

+    /* put sample parameters */

+    c->bit_rate = 64000;

+

+    /* check that the encoder supports s16 pcm input */

+    c->sample_fmt = AV_SAMPLE_FMT_S16;

+    if (!check_sample_fmt(codec, c->sample_fmt)) {

+        fprintf(stderr, "Encoder does not support sample format %s",

+                av_get_sample_fmt_name(c->sample_fmt));

+        exit(1);

+    }

+

+    /* select other audio parameters supported by the encoder */

+    c->sample_rate    = select_sample_rate(codec);

+    c->channel_layout = select_channel_layout(codec);

+    c->channels       = av_get_channel_layout_nb_channels(c->channel_layout);

+

+    /* open it */

+    if (avcodec_open2(c, codec, NULL) < 0) {

+        fprintf(stderr, "Could not open codec\n");

+        exit(1);

+    }

+

+    f = fopen(filename, "wb");

+    if (!f) {

+        fprintf(stderr, "Could not open %s\n", filename);

+        exit(1);

+    }

+

+    /* frame containing input raw audio */

+    frame = av_frame_alloc();

+    if (!frame) {

+        fprintf(stderr, "Could not allocate audio frame\n");

+        exit(1);

+    }

+

+    frame->nb_samples     = c->frame_size;

+    frame->format         = c->sample_fmt;

+    frame->channel_layout = c->channel_layout;

+

+    /* the codec gives us the frame size, in samples,

+     * we calculate the size of the samples buffer in bytes */

+    buffer_size = av_samples_get_buffer_size(NULL, c->channels, c->frame_size,

+                                             c->sample_fmt, 0);

+    if (buffer_size < 0) {

+        fprintf(stderr, "Could not get sample buffer size\n");

+        exit(1);

+    }

+    samples = av_malloc(buffer_size);

+    if (!samples) {

+        fprintf(stderr, "Could not allocate %d bytes for samples buffer\n",

+                buffer_size);

+        exit(1);

+    }